cpython-lru_cache-weakref: Lib/random.py annotate

annotate Lib/random.py @ 37850:ebe59cd18273

Use explicit relative import for an, ehm, relative import.

author	Thomas Wouters <thomas@python.org>
date	Tue, 18 Apr 2006 21:41:36 +0000
parents	3e5c07faab11
children	f731859e9b3b 1ca012ce427e

rev	line source
11707 6f4146846337 The third and final doc-string sweep by Ka-Ping Yee. Guido van Rossum <guido@python.org> parents: 11200 diff changeset	1 """Random variable generators.
6f4146846337 The third and final doc-string sweep by Ka-Ping Yee. Guido van Rossum <guido@python.org> parents: 11200 diff changeset	2
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	3 integers
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	4 --------
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	5 uniform within range
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	6
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	7 sequences
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	8 ---------
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	9 pick random element
26155 8ceb455f5541 SF patch 629637: Add sample(population, k) method to the random module. Raymond Hettinger <python@rcn.com> parents: 24861 diff changeset	10 pick random sample
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	11 generate random permutation
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	12
11707 6f4146846337 The third and final doc-string sweep by Ka-Ping Yee. Guido van Rossum <guido@python.org> parents: 11200 diff changeset	13 distributions on the real line:
6f4146846337 The third and final doc-string sweep by Ka-Ping Yee. Guido van Rossum <guido@python.org> parents: 11200 diff changeset	14 ------------------------------
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	15 uniform
11707 6f4146846337 The third and final doc-string sweep by Ka-Ping Yee. Guido van Rossum <guido@python.org> parents: 11200 diff changeset	16 normal (Gaussian)
6f4146846337 The third and final doc-string sweep by Ka-Ping Yee. Guido van Rossum <guido@python.org> parents: 11200 diff changeset	17 lognormal
6f4146846337 The third and final doc-string sweep by Ka-Ping Yee. Guido van Rossum <guido@python.org> parents: 11200 diff changeset	18 negative exponential
6f4146846337 The third and final doc-string sweep by Ka-Ping Yee. Guido van Rossum <guido@python.org> parents: 11200 diff changeset	19 gamma
6f4146846337 The third and final doc-string sweep by Ka-Ping Yee. Guido van Rossum <guido@python.org> parents: 11200 diff changeset	20 beta
26829 f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	21 pareto
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	22 Weibull
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	23
11707 6f4146846337 The third and final doc-string sweep by Ka-Ping Yee. Guido van Rossum <guido@python.org> parents: 11200 diff changeset	24 distributions on the circle (angles 0 to 2pi)
6f4146846337 The third and final doc-string sweep by Ka-Ping Yee. Guido van Rossum <guido@python.org> parents: 11200 diff changeset	25 ---------------------------------------------
6f4146846337 The third and final doc-string sweep by Ka-Ping Yee. Guido van Rossum <guido@python.org> parents: 11200 diff changeset	26 circular uniform
6f4146846337 The third and final doc-string sweep by Ka-Ping Yee. Guido van Rossum <guido@python.org> parents: 11200 diff changeset	27 von Mises
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	28
26829 f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	29 General notes on the underlying Mersenne Twister core generator:
16272 835e9dd54bfb The combo of getstate/setstate/jumpahead is very powerful, but needs Tim Peters <tim.peters@gmail.com> parents: 16271 diff changeset	30
26829 f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	31 * The period is 2**19937-1.
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	32 * It is one of the most extensively tested generators in existence
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	33 * Without a direct way to compute N steps forward, the
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	34 semantics of jumpahead(n) are weakened to simply jump
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	35 to another distant state and rely on the large period
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	36 to avoid overlapping sequences.
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	37 * The random() method is implemented in C, executes in
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	38 a single Python step, and is, therefore, threadsafe.
16272 835e9dd54bfb The combo of getstate/setstate/jumpahead is very powerful, but needs Tim Peters <tim.peters@gmail.com> parents: 16271 diff changeset	39
11707 6f4146846337 The third and final doc-string sweep by Ka-Ping Yee. Guido van Rossum <guido@python.org> parents: 11200 diff changeset	40 """
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	41
30649 8841d34a2c37 SF bug #812202: randint is always even Raymond Hettinger <python@rcn.com> parents: 30346 diff changeset	42 from warnings import warn as _warn
8841d34a2c37 SF bug #812202: randint is always even Raymond Hettinger <python@rcn.com> parents: 30346 diff changeset	43 from types import MethodType as _MethodType, BuiltinMethodType as _BuiltinMethodType
35359 c5bf5685267b Implement random.sample() using sets instead of dicts. Raymond Hettinger <python@rcn.com> parents: 34942 diff changeset	44 from math import log as _log, exp as _exp, pi as _pi, e as _e, ceil as _ceil
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	45 from math import sqrt as _sqrt, acos as _acos, cos as _cos, sin as _sin
33409 8e23bd3d5b1a Fulfill Martin's request to use try/except rather than a "look before Raymond Hettinger <python@rcn.com> parents: 33399 diff changeset	46 from os import urandom as _urandom
8e23bd3d5b1a Fulfill Martin's request to use try/except rather than a "look before Raymond Hettinger <python@rcn.com> parents: 33399 diff changeset	47 from binascii import hexlify as _hexlify
8455 af9273b1073a Make gauss() semi-thread-safe. It can still give duplicate results, Guido van Rossum <guido@python.org> parents: 8393 diff changeset	48
26155 8ceb455f5541 SF patch 629637: Add sample(population, k) method to the random module. Raymond Hettinger <python@rcn.com> parents: 24861 diff changeset	49 __all__ = ["Random","seed","random","uniform","randint","choice","sample",
16613 f68dbffff927 bunch more __all__ lists Skip Montanaro <skip@pobox.com> parents: 16386 diff changeset	50 "randrange","shuffle","normalvariate","lognormvariate",
30068 171814f5dcc6 Removed deprecated functions Raymond Hettinger <python@rcn.com> parents: 29586 diff changeset	51 "expovariate","vonmisesvariate","gammavariate",
171814f5dcc6 Removed deprecated functions Raymond Hettinger <python@rcn.com> parents: 29586 diff changeset	52 "gauss","betavariate","paretovariate","weibullvariate",
33329 97fca735c8da Teach the random module about os.urandom(). Raymond Hettinger <python@rcn.com> parents: 32287 diff changeset	53 "getstate","setstate","jumpahead", "WichmannHill", "getrandbits",
33481 eacdc29606d8 SF #1027105: HardwareRandom should be renamed OSRandom Raymond Hettinger <python@rcn.com> parents: 33409 diff changeset	54 "SystemRandom"]
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	55
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	56 NV_MAGICCONST = 4 * _exp(-0.5)/_sqrt(2.0)
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	57 TWOPI = 2.0*_pi
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	58 LOG4 = _log(4.0)
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	59 SG_MAGICCONST = 1.0 + _log(4.5)
30649 8841d34a2c37 SF bug #812202: randint is always even Raymond Hettinger <python@rcn.com> parents: 30346 diff changeset	60 BPF = 53 # Number of bits in a float
33350 c44f083465f9 HardwareRandom: Go back to multiplying by 2*-BPF instead of using Tim Peters <tim.peters@gmail.com>* parents: 33349 diff changeset	61 RECIP_BPF = 2**-BPF
8393 7669ddf0e7d4 Add Interfaces to replace remaining needs for importing whrandom. Guido van Rossum <guido@python.org> parents: 7881 diff changeset	62
33329 97fca735c8da Teach the random module about os.urandom(). Raymond Hettinger <python@rcn.com> parents: 32287 diff changeset	63
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	64 # Translated by Guido van Rossum from C source provided by
26829 f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	65 # Adrian Baddeley. Adapted by Raymond Hettinger for use with
33349 ddba154c0e00 Take advantage of the math library's ldexp for assembling a float by Raymond Hettinger <python@rcn.com> parents: 33329 diff changeset	66 # the Mersenne Twister and os.urandom() core generators.
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	67
27131 e87d590a5de1 Much clearer when super() is used. Raymond Hettinger <python@rcn.com> parents: 27094 diff changeset	68 import _random
26829 f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	69
27131 e87d590a5de1 Much clearer when super() is used. Raymond Hettinger <python@rcn.com> parents: 27094 diff changeset	70 class Random(_random.Random):
23531 a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	71 """Random number generator base class used by bound module functions.
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	72
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	73 Used to instantiate instances of Random to get generators that don't
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	74 share state. Especially useful for multi-threaded programs, creating
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	75 a different instance of Random for each thread, and using the jumpahead()
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	76 method to ensure that the generated sequences seen by each thread don't
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	77 overlap.
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	78
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	79 Class Random can also be subclassed if you want to use a different basic
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	80 generator of your own devising: in that case, override the following
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	81 methods: random(), seed(), getstate(), setstate() and jumpahead().
30649 8841d34a2c37 SF bug #812202: randint is always even Raymond Hettinger <python@rcn.com> parents: 30346 diff changeset	82 Optionally, implement a getrandombits() method so that randrange()
8841d34a2c37 SF bug #812202: randint is always even Raymond Hettinger <python@rcn.com> parents: 30346 diff changeset	83 can cover arbitrarily large ranges.
23536 0a4c92559a0b Whitespace normalized. Raymond Hettinger <python@rcn.com> parents: 23531 diff changeset	84
23531 a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	85 """
8393 7669ddf0e7d4 Add Interfaces to replace remaining needs for importing whrandom. Guido van Rossum <guido@python.org> parents: 7881 diff changeset	86
26829 f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	87 VERSION = 2 # used by getstate/setstate
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	88
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	89 def __init__(self, x=None):
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	90 """Initialize an instance.
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	91
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	92 Optional argument x controls seeding, as for Random.seed().
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	93 """
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	94
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	95 self.seed(x)
26829 f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	96 self.gauss_next = None
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	97
16379 5f0683a69efc Change random.seed() so that it can get at the full range of possible Tim Peters <tim.peters@gmail.com> parents: 16292 diff changeset	98 def seed(self, a=None):
5f0683a69efc Change random.seed() so that it can get at the full range of possible Tim Peters <tim.peters@gmail.com> parents: 16292 diff changeset	99 """Initialize internal state from hashable object.
5f0683a69efc Change random.seed() so that it can get at the full range of possible Tim Peters <tim.peters@gmail.com> parents: 16292 diff changeset	100
33481 eacdc29606d8 SF #1027105: HardwareRandom should be renamed OSRandom Raymond Hettinger <python@rcn.com> parents: 33409 diff changeset	101 None or no argument seeds from current time or from an operating
eacdc29606d8 SF #1027105: HardwareRandom should be renamed OSRandom Raymond Hettinger <python@rcn.com> parents: 33409 diff changeset	102 system specific randomness source if available.
8393 7669ddf0e7d4 Add Interfaces to replace remaining needs for importing whrandom. Guido van Rossum <guido@python.org> parents: 7881 diff changeset	103
16386 c2555b4f38a3 Repaired a docstring. Tim Peters <tim.peters@gmail.com> parents: 16379 diff changeset	104 If a is not None or an int or long, hash(a) is used instead.
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	105 """
8393 7669ddf0e7d4 Add Interfaces to replace remaining needs for importing whrandom. Guido van Rossum <guido@python.org> parents: 7881 diff changeset	106
30114 9f6e2dee1892 SF bug #778964: bad seed in python 2.3 random Raymond Hettinger <python@rcn.com> parents: 30068 diff changeset	107 if a is None:
33409 8e23bd3d5b1a Fulfill Martin's request to use try/except rather than a "look before Raymond Hettinger <python@rcn.com> parents: 33399 diff changeset	108 try:
8e23bd3d5b1a Fulfill Martin's request to use try/except rather than a "look before Raymond Hettinger <python@rcn.com> parents: 33399 diff changeset	109 a = long(_hexlify(_urandom(16)), 16)
8e23bd3d5b1a Fulfill Martin's request to use try/except rather than a "look before Raymond Hettinger <python@rcn.com> parents: 33399 diff changeset	110 except NotImplementedError:
33329 97fca735c8da Teach the random module about os.urandom(). Raymond Hettinger <python@rcn.com> parents: 32287 diff changeset	111 import time
97fca735c8da Teach the random module about os.urandom(). Raymond Hettinger <python@rcn.com> parents: 32287 diff changeset	112 a = long(time.time() * 256) # use fractional seconds
97fca735c8da Teach the random module about os.urandom(). Raymond Hettinger <python@rcn.com> parents: 32287 diff changeset	113
27131 e87d590a5de1 Much clearer when super() is used. Raymond Hettinger <python@rcn.com> parents: 27094 diff changeset	114 super(Random, self).seed(a)
23380 9be01b7b6c80 random.gauss() uses a piece of hidden state used by nothing else, Tim Peters <tim.peters@gmail.com> parents: 23023 diff changeset	115 self.gauss_next = None
9be01b7b6c80 random.gauss() uses a piece of hidden state used by nothing else, Tim Peters <tim.peters@gmail.com> parents: 23023 diff changeset	116
16265 d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	117 def getstate(self):
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	118 """Return internal state; can be passed to setstate() later."""
27131 e87d590a5de1 Much clearer when super() is used. Raymond Hettinger <python@rcn.com> parents: 27094 diff changeset	119 return self.VERSION, super(Random, self).getstate(), self.gauss_next
16265 d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	120
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	121 def setstate(self, state):
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	122 """Restore internal state from object returned by getstate()."""
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	123 version = state[0]
26829 f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	124 if version == 2:
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	125 version, internalstate, self.gauss_next = state
27131 e87d590a5de1 Much clearer when super() is used. Raymond Hettinger <python@rcn.com> parents: 27094 diff changeset	126 super(Random, self).setstate(internalstate)
16265 d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	127 else:
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	128 raise ValueError("state with version %s passed to "
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	129 "Random.setstate() of version %s" %
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	130 (version, self.VERSION))
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	131
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	132 ## ---- Methods below this point do not need to be overridden when
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	133 ## ---- subclassing for the purpose of using a different core generator.
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	134
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	135 ## -------------------- pickle support -------------------
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	136
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	137 def __getstate__(self): # for pickle
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	138 return self.getstate()
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	139
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	140 def __setstate__(self, state): # for pickle
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	141 self.setstate(state)
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	142
29586 8b163370372d SF bug #759889: Pickling of Random is broken Raymond Hettinger <python@rcn.com> parents: 29539 diff changeset	143 def __reduce__(self):
8b163370372d SF bug #759889: Pickling of Random is broken Raymond Hettinger <python@rcn.com> parents: 29539 diff changeset	144 return self.__class__, (), self.getstate()
8b163370372d SF bug #759889: Pickling of Random is broken Raymond Hettinger <python@rcn.com> parents: 29539 diff changeset	145
16265 d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	146 ## -------------------- integer methods -------------------
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	147
30649 8841d34a2c37 SF bug #812202: randint is always even Raymond Hettinger <python@rcn.com> parents: 30346 diff changeset	148 def randrange(self, start, stop=None, step=1, int=int, default=None,
8841d34a2c37 SF bug #812202: randint is always even Raymond Hettinger <python@rcn.com> parents: 30346 diff changeset	149 maxwidth=1L<<BPF):
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	150 """Choose a random item from range(start, stop[, step]).
8393 7669ddf0e7d4 Add Interfaces to replace remaining needs for importing whrandom. Guido van Rossum <guido@python.org> parents: 7881 diff changeset	151
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	152 This fixes the problem with randint() which includes the
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	153 endpoint; in Python this is usually not what you want.
30649 8841d34a2c37 SF bug #812202: randint is always even Raymond Hettinger <python@rcn.com> parents: 30346 diff changeset	154 Do not supply the 'int', 'default', and 'maxwidth' arguments.
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	155 """
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	156
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	157 # This code is a bit messy to make it fast for the
24861 4e795fe9f54b SF bug 594996: OverflowError in random.randrange Tim Peters <tim.peters@gmail.com> parents: 23536 diff changeset	158 # common case while still doing adequate error checking.
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	159 istart = int(start)
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	160 if istart != start:
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	161 raise ValueError, "non-integer arg 1 for randrange()"
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	162 if stop is default:
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	163 if istart > 0:
30649 8841d34a2c37 SF bug #812202: randint is always even Raymond Hettinger <python@rcn.com> parents: 30346 diff changeset	164 if istart >= maxwidth:
8841d34a2c37 SF bug #812202: randint is always even Raymond Hettinger <python@rcn.com> parents: 30346 diff changeset	165 return self._randbelow(istart)
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	166 return int(self.random() * istart)
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	167 raise ValueError, "empty range for randrange()"
24861 4e795fe9f54b SF bug 594996: OverflowError in random.randrange Tim Peters <tim.peters@gmail.com> parents: 23536 diff changeset	168
4e795fe9f54b SF bug 594996: OverflowError in random.randrange Tim Peters <tim.peters@gmail.com> parents: 23536 diff changeset	169 # stop argument supplied.
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	170 istop = int(stop)
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	171 if istop != stop:
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	172 raise ValueError, "non-integer stop for randrange()"
30649 8841d34a2c37 SF bug #812202: randint is always even Raymond Hettinger <python@rcn.com> parents: 30346 diff changeset	173 width = istop - istart
8841d34a2c37 SF bug #812202: randint is always even Raymond Hettinger <python@rcn.com> parents: 30346 diff changeset	174 if step == 1 and width > 0:
29539 fafb6eb0f97e randrange(): Repaired my overly optimistic rewrite, and added comments Tim Peters <tim.peters@gmail.com> parents: 29538 diff changeset	175 # Note that
30649 8841d34a2c37 SF bug #812202: randint is always even Raymond Hettinger <python@rcn.com> parents: 30346 diff changeset	176 # int(istart + self.random()*width)
29539 fafb6eb0f97e randrange(): Repaired my overly optimistic rewrite, and added comments Tim Peters <tim.peters@gmail.com> parents: 29538 diff changeset	177 # instead would be incorrect. For example, consider istart
fafb6eb0f97e randrange(): Repaired my overly optimistic rewrite, and added comments Tim Peters <tim.peters@gmail.com> parents: 29538 diff changeset	178 # = -2 and istop = 0. Then the guts would be in
fafb6eb0f97e randrange(): Repaired my overly optimistic rewrite, and added comments Tim Peters <tim.peters@gmail.com> parents: 29538 diff changeset	179 # -2.0 to 0.0 exclusive on both ends (ignoring that random()
fafb6eb0f97e randrange(): Repaired my overly optimistic rewrite, and added comments Tim Peters <tim.peters@gmail.com> parents: 29538 diff changeset	180 # might return 0.0), and because int() truncates toward 0, the
fafb6eb0f97e randrange(): Repaired my overly optimistic rewrite, and added comments Tim Peters <tim.peters@gmail.com> parents: 29538 diff changeset	181 # final result would be -1 or 0 (instead of -2 or -1).
30649 8841d34a2c37 SF bug #812202: randint is always even Raymond Hettinger <python@rcn.com> parents: 30346 diff changeset	182 # istart + int(self.random()*width)
29539 fafb6eb0f97e randrange(): Repaired my overly optimistic rewrite, and added comments Tim Peters <tim.peters@gmail.com> parents: 29538 diff changeset	183 # would also be incorrect, for a subtler reason: the RHS
fafb6eb0f97e randrange(): Repaired my overly optimistic rewrite, and added comments Tim Peters <tim.peters@gmail.com> parents: 29538 diff changeset	184 # can return a long, and then randrange() would also return
fafb6eb0f97e randrange(): Repaired my overly optimistic rewrite, and added comments Tim Peters <tim.peters@gmail.com> parents: 29538 diff changeset	185 # a long, but we're supposed to return an int (for backward
fafb6eb0f97e randrange(): Repaired my overly optimistic rewrite, and added comments Tim Peters <tim.peters@gmail.com> parents: 29538 diff changeset	186 # compatibility).
30649 8841d34a2c37 SF bug #812202: randint is always even Raymond Hettinger <python@rcn.com> parents: 30346 diff changeset	187
8841d34a2c37 SF bug #812202: randint is always even Raymond Hettinger <python@rcn.com> parents: 30346 diff changeset	188 if width >= maxwidth:
31389 aca1ce1b4b61 Whitespace normalization. Tim Peters <tim.peters@gmail.com> parents: 30865 diff changeset	189 return int(istart + self._randbelow(width))
30649 8841d34a2c37 SF bug #812202: randint is always even Raymond Hettinger <python@rcn.com> parents: 30346 diff changeset	190 return int(istart + int(self.random()*width))
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	191 if step == 1:
30649 8841d34a2c37 SF bug #812202: randint is always even Raymond Hettinger <python@rcn.com> parents: 30346 diff changeset	192 raise ValueError, "empty range for randrange() (%d,%d, %d)" % (istart, istop, width)
24861 4e795fe9f54b SF bug 594996: OverflowError in random.randrange Tim Peters <tim.peters@gmail.com> parents: 23536 diff changeset	193
4e795fe9f54b SF bug 594996: OverflowError in random.randrange Tim Peters <tim.peters@gmail.com> parents: 23536 diff changeset	194 # Non-unit step argument supplied.
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	195 istep = int(step)
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	196 if istep != step:
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	197 raise ValueError, "non-integer step for randrange()"
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	198 if istep > 0:
33597 355b15e4a4da Use floor division operator. Raymond Hettinger <python@rcn.com> parents: 33481 diff changeset	199 n = (width + istep - 1) // istep
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	200 elif istep < 0:
33597 355b15e4a4da Use floor division operator. Raymond Hettinger <python@rcn.com> parents: 33481 diff changeset	201 n = (width + istep + 1) // istep
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	202 else:
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	203 raise ValueError, "zero step for randrange()"
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	204
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	205 if n <= 0:
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	206 raise ValueError, "empty range for randrange()"
30649 8841d34a2c37 SF bug #812202: randint is always even Raymond Hettinger <python@rcn.com> parents: 30346 diff changeset	207
8841d34a2c37 SF bug #812202: randint is always even Raymond Hettinger <python@rcn.com> parents: 30346 diff changeset	208 if n >= maxwidth:
8841d34a2c37 SF bug #812202: randint is always even Raymond Hettinger <python@rcn.com> parents: 30346 diff changeset	209 return istart + self._randbelow(n)
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	210 return istart + istepint(self.random() n)
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	211
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	212 def randint(self, a, b):
16265 d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	213 """Return random integer in range [a, b], including both end points.
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	214 """
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	215
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	216 return self.randrange(a, b+1)
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	217
30649 8841d34a2c37 SF bug #812202: randint is always even Raymond Hettinger <python@rcn.com> parents: 30346 diff changeset	218 def _randbelow(self, n, _log=_log, int=int, _maxwidth=1L<<BPF,
8841d34a2c37 SF bug #812202: randint is always even Raymond Hettinger <python@rcn.com> parents: 30346 diff changeset	219 _Method=_MethodType, _BuiltinMethod=_BuiltinMethodType):
8841d34a2c37 SF bug #812202: randint is always even Raymond Hettinger <python@rcn.com> parents: 30346 diff changeset	220 """Return a random int in the range [0,n)
8841d34a2c37 SF bug #812202: randint is always even Raymond Hettinger <python@rcn.com> parents: 30346 diff changeset	221
8841d34a2c37 SF bug #812202: randint is always even Raymond Hettinger <python@rcn.com> parents: 30346 diff changeset	222 Handles the case where n has more bits than returned
8841d34a2c37 SF bug #812202: randint is always even Raymond Hettinger <python@rcn.com> parents: 30346 diff changeset	223 by a single call to the underlying generator.
8841d34a2c37 SF bug #812202: randint is always even Raymond Hettinger <python@rcn.com> parents: 30346 diff changeset	224 """
8841d34a2c37 SF bug #812202: randint is always even Raymond Hettinger <python@rcn.com> parents: 30346 diff changeset	225
8841d34a2c37 SF bug #812202: randint is always even Raymond Hettinger <python@rcn.com> parents: 30346 diff changeset	226 try:
8841d34a2c37 SF bug #812202: randint is always even Raymond Hettinger <python@rcn.com> parents: 30346 diff changeset	227 getrandbits = self.getrandbits
8841d34a2c37 SF bug #812202: randint is always even Raymond Hettinger <python@rcn.com> parents: 30346 diff changeset	228 except AttributeError:
8841d34a2c37 SF bug #812202: randint is always even Raymond Hettinger <python@rcn.com> parents: 30346 diff changeset	229 pass
8841d34a2c37 SF bug #812202: randint is always even Raymond Hettinger <python@rcn.com> parents: 30346 diff changeset	230 else:
8841d34a2c37 SF bug #812202: randint is always even Raymond Hettinger <python@rcn.com> parents: 30346 diff changeset	231 # Only call self.getrandbits if the original random() builtin method
8841d34a2c37 SF bug #812202: randint is always even Raymond Hettinger <python@rcn.com> parents: 30346 diff changeset	232 # has not been overridden or if a new getrandbits() was supplied.
8841d34a2c37 SF bug #812202: randint is always even Raymond Hettinger <python@rcn.com> parents: 30346 diff changeset	233 # This assures that the two methods correspond.
8841d34a2c37 SF bug #812202: randint is always even Raymond Hettinger <python@rcn.com> parents: 30346 diff changeset	234 if type(self.random) is _BuiltinMethod or type(getrandbits) is _Method:
8841d34a2c37 SF bug #812202: randint is always even Raymond Hettinger <python@rcn.com> parents: 30346 diff changeset	235 k = int(1.00001 + _log(n-1, 2.0)) # 2k > n-1 > 2(k-2)
8841d34a2c37 SF bug #812202: randint is always even Raymond Hettinger <python@rcn.com> parents: 30346 diff changeset	236 r = getrandbits(k)
8841d34a2c37 SF bug #812202: randint is always even Raymond Hettinger <python@rcn.com> parents: 30346 diff changeset	237 while r >= n:
8841d34a2c37 SF bug #812202: randint is always even Raymond Hettinger <python@rcn.com> parents: 30346 diff changeset	238 r = getrandbits(k)
8841d34a2c37 SF bug #812202: randint is always even Raymond Hettinger <python@rcn.com> parents: 30346 diff changeset	239 return r
8841d34a2c37 SF bug #812202: randint is always even Raymond Hettinger <python@rcn.com> parents: 30346 diff changeset	240 if n >= _maxwidth:
8841d34a2c37 SF bug #812202: randint is always even Raymond Hettinger <python@rcn.com> parents: 30346 diff changeset	241 _warn("Underlying random() generator does not supply \n"
8841d34a2c37 SF bug #812202: randint is always even Raymond Hettinger <python@rcn.com> parents: 30346 diff changeset	242 "enough bits to choose from a population range this large")
8841d34a2c37 SF bug #812202: randint is always even Raymond Hettinger <python@rcn.com> parents: 30346 diff changeset	243 return int(self.random() * n)
8841d34a2c37 SF bug #812202: randint is always even Raymond Hettinger <python@rcn.com> parents: 30346 diff changeset	244
16265 d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	245 ## -------------------- sequence methods -------------------
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	246
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	247 def choice(self, seq):
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	248 """Choose a random element from a non-empty sequence."""
32287 854a2417d35e Fix typo in comment. Raymond Hettinger <python@rcn.com> parents: 32255 diff changeset	249 return seq[int(self.random() * len(seq))] # raises IndexError if seq is empty
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	250
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	251 def shuffle(self, x, random=None, int=int):
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	252 """x, random=random.random -> shuffle list x in place; return None.
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	253
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	254 Optional arg random is a 0-argument function returning a random
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	255 float in [0.0, 1.0); by default, the standard random.random.
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	256
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	257 Note that for even rather small len(x), the total number of
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	258 permutations of x is larger than the period of most random number
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	259 generators; this implies that "most" permutations of a long
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	260 sequence can never be generated.
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	261 """
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	262
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	263 if random is None:
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	264 random = self.random
30865 41c4e143e6e6 Implement and apply PEP 322, reverse iteration Raymond Hettinger <python@rcn.com> parents: 30680 diff changeset	265 for i in reversed(xrange(1, len(x))):
16265 d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	266 # pick an element in x[:i+1] with which to exchange x[i]
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	267 j = int(random() * (i+1))
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	268 x[i], x[j] = x[j], x[i]
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	269
29430 b80a22250e4f SF bug #753602: random.sample not properly documented Raymond Hettinger <python@rcn.com> parents: 29250 diff changeset	270 def sample(self, population, k):
26155 8ceb455f5541 SF patch 629637: Add sample(population, k) method to the random module. Raymond Hettinger <python@rcn.com> parents: 24861 diff changeset	271 """Chooses k unique random elements from a population sequence.
8ceb455f5541 SF patch 629637: Add sample(population, k) method to the random module. Raymond Hettinger <python@rcn.com> parents: 24861 diff changeset	272
26178 83ae4a902df0 Improved clarity and thoroughness of docstring. Raymond Hettinger <python@rcn.com> parents: 26172 diff changeset	273 Returns a new list containing elements from the population while
83ae4a902df0 Improved clarity and thoroughness of docstring. Raymond Hettinger <python@rcn.com> parents: 26172 diff changeset	274 leaving the original population unchanged. The resulting list is
83ae4a902df0 Improved clarity and thoroughness of docstring. Raymond Hettinger <python@rcn.com> parents: 26172 diff changeset	275 in selection order so that all sub-slices will also be valid random
83ae4a902df0 Improved clarity and thoroughness of docstring. Raymond Hettinger <python@rcn.com> parents: 26172 diff changeset	276 samples. This allows raffle winners (the sample) to be partitioned
83ae4a902df0 Improved clarity and thoroughness of docstring. Raymond Hettinger <python@rcn.com> parents: 26172 diff changeset	277 into grand prize and second place winners (the subslices).
26155 8ceb455f5541 SF patch 629637: Add sample(population, k) method to the random module. Raymond Hettinger <python@rcn.com> parents: 24861 diff changeset	278
26178 83ae4a902df0 Improved clarity and thoroughness of docstring. Raymond Hettinger <python@rcn.com> parents: 26172 diff changeset	279 Members of the population need not be hashable or unique. If the
83ae4a902df0 Improved clarity and thoroughness of docstring. Raymond Hettinger <python@rcn.com> parents: 26172 diff changeset	280 population contains repeats, then each occurrence is a possible
83ae4a902df0 Improved clarity and thoroughness of docstring. Raymond Hettinger <python@rcn.com> parents: 26172 diff changeset	281 selection in the sample.
26155 8ceb455f5541 SF patch 629637: Add sample(population, k) method to the random module. Raymond Hettinger <python@rcn.com> parents: 24861 diff changeset	282
26178 83ae4a902df0 Improved clarity and thoroughness of docstring. Raymond Hettinger <python@rcn.com> parents: 26172 diff changeset	283 To choose a sample in a range of integers, use xrange as an argument.
83ae4a902df0 Improved clarity and thoroughness of docstring. Raymond Hettinger <python@rcn.com> parents: 26172 diff changeset	284 This is especially fast and space efficient for sampling from a
83ae4a902df0 Improved clarity and thoroughness of docstring. Raymond Hettinger <python@rcn.com> parents: 26172 diff changeset	285 large population: sample(xrange(10000000), 60)
26155 8ceb455f5541 SF patch 629637: Add sample(population, k) method to the random module. Raymond Hettinger <python@rcn.com> parents: 24861 diff changeset	286 """
8ceb455f5541 SF patch 629637: Add sample(population, k) method to the random module. Raymond Hettinger <python@rcn.com> parents: 24861 diff changeset	287
26178 83ae4a902df0 Improved clarity and thoroughness of docstring. Raymond Hettinger <python@rcn.com> parents: 26172 diff changeset	288 # Sampling without replacement entails tracking either potential
35359 c5bf5685267b Implement random.sample() using sets instead of dicts. Raymond Hettinger <python@rcn.com> parents: 34942 diff changeset	289 # selections (the pool) in a list or previous selections in a set.
26178 83ae4a902df0 Improved clarity and thoroughness of docstring. Raymond Hettinger <python@rcn.com> parents: 26172 diff changeset	290
31578 8183dd1a4fe6 Reflow long line. Jeremy Hylton <jeremy@alum.mit.edu> parents: 31389 diff changeset	291 # When the number of selections is small compared to the
8183dd1a4fe6 Reflow long line. Jeremy Hylton <jeremy@alum.mit.edu> parents: 31389 diff changeset	292 # population, then tracking selections is efficient, requiring
35359 c5bf5685267b Implement random.sample() using sets instead of dicts. Raymond Hettinger <python@rcn.com> parents: 34942 diff changeset	293 # only a small set and an occasional reselection. For
31578 8183dd1a4fe6 Reflow long line. Jeremy Hylton <jeremy@alum.mit.edu> parents: 31389 diff changeset	294 # a larger number of selections, the pool tracking method is
8183dd1a4fe6 Reflow long line. Jeremy Hylton <jeremy@alum.mit.edu> parents: 31389 diff changeset	295 # preferred since the list takes less space than the
35359 c5bf5685267b Implement random.sample() using sets instead of dicts. Raymond Hettinger <python@rcn.com> parents: 34942 diff changeset	296 # set and it doesn't suffer from frequent reselections.
26178 83ae4a902df0 Improved clarity and thoroughness of docstring. Raymond Hettinger <python@rcn.com> parents: 26172 diff changeset	297
26155 8ceb455f5541 SF patch 629637: Add sample(population, k) method to the random module. Raymond Hettinger <python@rcn.com> parents: 24861 diff changeset	298 n = len(population)
8ceb455f5541 SF patch 629637: Add sample(population, k) method to the random module. Raymond Hettinger <python@rcn.com> parents: 24861 diff changeset	299 if not 0 <= k <= n:
8ceb455f5541 SF patch 629637: Add sample(population, k) method to the random module. Raymond Hettinger <python@rcn.com> parents: 24861 diff changeset	300 raise ValueError, "sample larger than population"
27080 2ae1d17572da Remove the random=None nonsense from sample() before it gets set in stone. Raymond Hettinger <python@rcn.com> parents: 26829 diff changeset	301 random = self.random
29430 b80a22250e4f SF bug #753602: random.sample not properly documented Raymond Hettinger <python@rcn.com> parents: 29250 diff changeset	302 _int = int
26178 83ae4a902df0 Improved clarity and thoroughness of docstring. Raymond Hettinger <python@rcn.com> parents: 26172 diff changeset	303 result = [None] * k
35359 c5bf5685267b Implement random.sample() using sets instead of dicts. Raymond Hettinger <python@rcn.com> parents: 34942 diff changeset	304 setsize = 21 # size of a small set minus size of an empty list
c5bf5685267b Implement random.sample() using sets instead of dicts. Raymond Hettinger <python@rcn.com> parents: 34942 diff changeset	305 if k > 5:
35465 3e5c07faab11 Whitespace normalization (via reindent.py). Tim Peters <tim.peters@gmail.com> parents: 35359 diff changeset	306 setsize += 4 ** _ceil(_log(k * 3, 4)) # table size for big sets
35359 c5bf5685267b Implement random.sample() using sets instead of dicts. Raymond Hettinger <python@rcn.com> parents: 34942 diff changeset	307 if n <= setsize: # is an n-length list smaller than a k-length set
26266 42279f7d244d Improve comments. Clarify docs. Raymond Hettinger <python@rcn.com> parents: 26178 diff changeset	308 pool = list(population)
42279f7d244d Improve comments. Clarify docs. Raymond Hettinger <python@rcn.com> parents: 26178 diff changeset	309 for i in xrange(k): # invariant: non-selected at [0,n-i)
29430 b80a22250e4f SF bug #753602: random.sample not properly documented Raymond Hettinger <python@rcn.com> parents: 29250 diff changeset	310 j = _int(random() * (n-i))
26266 42279f7d244d Improve comments. Clarify docs. Raymond Hettinger <python@rcn.com> parents: 26178 diff changeset	311 result[i] = pool[j]
27080 2ae1d17572da Remove the random=None nonsense from sample() before it gets set in stone. Raymond Hettinger <python@rcn.com> parents: 26829 diff changeset	312 pool[j] = pool[n-i-1] # move non-selected item into vacancy
26178 83ae4a902df0 Improved clarity and thoroughness of docstring. Raymond Hettinger <python@rcn.com> parents: 26172 diff changeset	313 else:
30346 aaf6b6a8510b SF bug #801342: Bug (documentation or real, your choice) in random.sample. Raymond Hettinger <python@rcn.com> parents: 30243 diff changeset	314 try:
aaf6b6a8510b SF bug #801342: Bug (documentation or real, your choice) in random.sample. Raymond Hettinger <python@rcn.com> parents: 30243 diff changeset	315 n > 0 and (population[0], population[n//2], population[n-1])
35359 c5bf5685267b Implement random.sample() using sets instead of dicts. Raymond Hettinger <python@rcn.com> parents: 34942 diff changeset	316 except (TypeError, KeyError): # handle non-sequence iterables
30346 aaf6b6a8510b SF bug #801342: Bug (documentation or real, your choice) in random.sample. Raymond Hettinger <python@rcn.com> parents: 30243 diff changeset	317 population = tuple(population)
35359 c5bf5685267b Implement random.sample() using sets instead of dicts. Raymond Hettinger <python@rcn.com> parents: 34942 diff changeset	318 selected = set()
c5bf5685267b Implement random.sample() using sets instead of dicts. Raymond Hettinger <python@rcn.com> parents: 34942 diff changeset	319 selected_add = selected.add
26178 83ae4a902df0 Improved clarity and thoroughness of docstring. Raymond Hettinger <python@rcn.com> parents: 26172 diff changeset	320 for i in xrange(k):
29430 b80a22250e4f SF bug #753602: random.sample not properly documented Raymond Hettinger <python@rcn.com> parents: 29250 diff changeset	321 j = _int(random() * n)
26266 42279f7d244d Improve comments. Clarify docs. Raymond Hettinger <python@rcn.com> parents: 26178 diff changeset	322 while j in selected:
29430 b80a22250e4f SF bug #753602: random.sample not properly documented Raymond Hettinger <python@rcn.com> parents: 29250 diff changeset	323 j = _int(random() * n)
35359 c5bf5685267b Implement random.sample() using sets instead of dicts. Raymond Hettinger <python@rcn.com> parents: 34942 diff changeset	324 selected_add(j)
c5bf5685267b Implement random.sample() using sets instead of dicts. Raymond Hettinger <python@rcn.com> parents: 34942 diff changeset	325 result[i] = population[j]
26266 42279f7d244d Improve comments. Clarify docs. Raymond Hettinger <python@rcn.com> parents: 26178 diff changeset	326 return result
26155 8ceb455f5541 SF patch 629637: Add sample(population, k) method to the random module. Raymond Hettinger <python@rcn.com> parents: 24861 diff changeset	327
16265 d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	328 ## -------------------- real-valued distributions -------------------
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	329
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	330 ## -------------------- uniform distribution -------------------
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	331
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	332 def uniform(self, a, b):
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	333 """Get a random number in the range [a, b)."""
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	334 return a + (b-a) * self.random()
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	335
16265 d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	336 ## -------------------- normal distribution --------------------
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	337
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	338 def normalvariate(self, mu, sigma):
23531 a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	339 """Normal distribution.
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	340
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	341 mu is the mean, and sigma is the standard deviation.
23536 0a4c92559a0b Whitespace normalized. Raymond Hettinger <python@rcn.com> parents: 23531 diff changeset	342
23531 a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	343 """
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	344 # mu = mean, sigma = standard deviation
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	345
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	346 # Uses Kinderman and Monahan method. Reference: Kinderman,
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	347 # A.J. and Monahan, J.F., "Computer generation of random
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	348 # variables using the ratio of uniform deviates", ACM Trans
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	349 # Math Software, 3, (1977), pp257-260.
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	350
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	351 random = self.random
34942 7287b41145ae SF patch #1191489: Simplify logic in random.py Raymond Hettinger <python@rcn.com> parents: 34312 diff changeset	352 while 1:
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	353 u1 = random()
27085 90350b5d3397 Correct long standing bugs in the methods for random distributions. Raymond Hettinger <python@rcn.com> parents: 27080 diff changeset	354 u2 = 1.0 - random()
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	355 z = NV_MAGICCONST*(u1-0.5)/u2
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	356 zz = z*z/4.0
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	357 if zz <= -_log(u2):
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	358 break
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	359 return mu + z*sigma
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	360
16265 d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	361 ## -------------------- lognormal distribution --------------------
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	362
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	363 def lognormvariate(self, mu, sigma):
23531 a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	364 """Log normal distribution.
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	365
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	366 If you take the natural logarithm of this distribution, you'll get a
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	367 normal distribution with mean mu and standard deviation sigma.
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	368 mu can have any value, and sigma must be greater than zero.
23536 0a4c92559a0b Whitespace normalized. Raymond Hettinger <python@rcn.com> parents: 23531 diff changeset	369
23531 a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	370 """
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	371 return _exp(self.normalvariate(mu, sigma))
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	372
16265 d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	373 ## -------------------- exponential distribution --------------------
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	374
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	375 def expovariate(self, lambd):
23531 a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	376 """Exponential distribution.
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	377
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	378 lambd is 1.0 divided by the desired mean. (The parameter would be
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	379 called "lambda", but that is a reserved word in Python.) Returned
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	380 values range from 0 to positive infinity.
23536 0a4c92559a0b Whitespace normalized. Raymond Hettinger <python@rcn.com> parents: 23531 diff changeset	381
23531 a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	382 """
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	383 # lambd: rate lambd = 1/mean
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	384 # ('lambda' is a Python reserved word)
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	385
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	386 random = self.random
15871 62aeefa01fdd Whitespace normalization. Tim Peters <tim.peters@gmail.com> parents: 14617 diff changeset	387 u = random()
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	388 while u <= 1e-7:
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	389 u = random()
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	390 return -_log(u)/lambd
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	391
16265 d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	392 ## -------------------- von Mises distribution --------------------
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	393
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	394 def vonmisesvariate(self, mu, kappa):
23531 a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	395 """Circular data distribution.
23536 0a4c92559a0b Whitespace normalized. Raymond Hettinger <python@rcn.com> parents: 23531 diff changeset	396
23531 a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	397 mu is the mean angle, expressed in radians between 0 and 2*pi, and
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	398 kappa is the concentration parameter, which must be greater than or
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	399 equal to zero. If kappa is equal to zero, this distribution reduces
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	400 to a uniform random angle over the range 0 to 2*pi.
23536 0a4c92559a0b Whitespace normalized. Raymond Hettinger <python@rcn.com> parents: 23531 diff changeset	401
23531 a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	402 """
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	403 # mu: mean angle (in radians between 0 and 2*pi)
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	404 # kappa: concentration parameter kappa (>= 0)
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	405 # if kappa = 0 generate uniform random angle
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	406
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	407 # Based upon an algorithm published in: Fisher, N.I.,
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	408 # "Statistical Analysis of Circular Data", Cambridge
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	409 # University Press, 1993.
7881 6370f1593c72 Correction to vonmisesvariate() by Magnus Kessler: it should take and Guido van Rossum <guido@python.org> parents: 7412 diff changeset	410
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	411 # Thanks to Magnus Kessler for a correction to the
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	412 # implementation of step 4.
7881 6370f1593c72 Correction to vonmisesvariate() by Magnus Kessler: it should take and Guido van Rossum <guido@python.org> parents: 7412 diff changeset	413
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	414 random = self.random
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	415 if kappa <= 1e-6:
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	416 return TWOPI * random()
7881 6370f1593c72 Correction to vonmisesvariate() by Magnus Kessler: it should take and Guido van Rossum <guido@python.org> parents: 7412 diff changeset	417
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	418 a = 1.0 + _sqrt(1.0 + 4.0 * kappa * kappa)
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	419 b = (a - _sqrt(2.0 * a))/(2.0 * kappa)
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	420 r = (1.0 + b * b)/(2.0 * b)
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	421
34942 7287b41145ae SF patch #1191489: Simplify logic in random.py Raymond Hettinger <python@rcn.com> parents: 34312 diff changeset	422 while 1:
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	423 u1 = random()
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	424
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	425 z = _cos(_pi * u1)
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	426 f = (1.0 + r * z)/(r + z)
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	427 c = kappa * (r - f)
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	428
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	429 u2 = random()
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	430
34942 7287b41145ae SF patch #1191489: Simplify logic in random.py Raymond Hettinger <python@rcn.com> parents: 34312 diff changeset	431 if u2 < c * (2.0 - c) or u2 <= c * _exp(1.0 - c):
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	432 break
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	433
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	434 u3 = random()
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	435 if u3 > 0.5:
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	436 theta = (mu % TWOPI) + _acos(f)
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	437 else:
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	438 theta = (mu % TWOPI) - _acos(f)
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	439
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	440 return theta
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	441
16265 d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	442 ## -------------------- gamma distribution --------------------
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	443
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	444 def gammavariate(self, alpha, beta):
23531 a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	445 """Gamma distribution. Not the gamma function!
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	446
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	447 Conditions on the parameters are alpha > 0 and beta > 0.
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	448
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	449 """
23521 a90faa5f9417 Whitespace normalization. Tim Peters <tim.peters@gmail.com> parents: 23451 diff changeset	450
23447 08ccb0f3e2d4 Closes patch 529408 deprecating random.stdgamma(). Raymond Hettinger <python@rcn.com> parents: 23442 diff changeset	451 # alpha > 0, beta > 0, mean is alphabeta, variance is alphabeta**2
23521 a90faa5f9417 Whitespace normalization. Tim Peters <tim.peters@gmail.com> parents: 23451 diff changeset	452
23451 273dd2508c57 Use spaces, not tabs for indents. Guido van Rossum <guido@python.org> parents: 23447 diff changeset	453 # Warning: a few older sources define the gamma distribution in terms
273dd2508c57 Use spaces, not tabs for indents. Guido van Rossum <guido@python.org> parents: 23447 diff changeset	454 # of alpha > -1.0
273dd2508c57 Use spaces, not tabs for indents. Guido van Rossum <guido@python.org> parents: 23447 diff changeset	455 if alpha <= 0.0 or beta <= 0.0:
273dd2508c57 Use spaces, not tabs for indents. Guido van Rossum <guido@python.org> parents: 23447 diff changeset	456 raise ValueError, 'gammavariate: alpha and beta must be > 0.0'
23521 a90faa5f9417 Whitespace normalization. Tim Peters <tim.peters@gmail.com> parents: 23451 diff changeset	457
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	458 random = self.random
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	459 if alpha > 1.0:
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	460
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	461 # Uses R.C.H. Cheng, "The generation of Gamma
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	462 # variables with non-integral shape parameters",
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	463 # Applied Statistics, (1977), 26, No. 1, p71-74
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	464
23442 b15896053933 Closes SF bug 527139. Moved temp variables inside guard. Raymond Hettinger <python@rcn.com> parents: 23380 diff changeset	465 ainv = _sqrt(2.0 * alpha - 1.0)
b15896053933 Closes SF bug 527139. Moved temp variables inside guard. Raymond Hettinger <python@rcn.com> parents: 23380 diff changeset	466 bbb = alpha - LOG4
b15896053933 Closes SF bug 527139. Moved temp variables inside guard. Raymond Hettinger <python@rcn.com> parents: 23380 diff changeset	467 ccc = alpha + ainv
23521 a90faa5f9417 Whitespace normalization. Tim Peters <tim.peters@gmail.com> parents: 23451 diff changeset	468
34942 7287b41145ae SF patch #1191489: Simplify logic in random.py Raymond Hettinger <python@rcn.com> parents: 34312 diff changeset	469 while 1:
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	470 u1 = random()
27085 90350b5d3397 Correct long standing bugs in the methods for random distributions. Raymond Hettinger <python@rcn.com> parents: 27080 diff changeset	471 if not 1e-7 < u1 < .9999999:
90350b5d3397 Correct long standing bugs in the methods for random distributions. Raymond Hettinger <python@rcn.com> parents: 27080 diff changeset	472 continue
90350b5d3397 Correct long standing bugs in the methods for random distributions. Raymond Hettinger <python@rcn.com> parents: 27080 diff changeset	473 u2 = 1.0 - random()
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	474 v = _log(u1/(1.0-u1))/ainv
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	475 x = alpha*_exp(v)
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	476 z = u1u1u2
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	477 r = bbb+ccc*v-x
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	478 if r + SG_MAGICCONST - 4.5*z >= 0.0 or r >= _log(z):
23447 08ccb0f3e2d4 Closes patch 529408 deprecating random.stdgamma(). Raymond Hettinger <python@rcn.com> parents: 23442 diff changeset	479 return x * beta
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	480
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	481 elif alpha == 1.0:
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	482 # expovariate(1)
15871 62aeefa01fdd Whitespace normalization. Tim Peters <tim.peters@gmail.com> parents: 14617 diff changeset	483 u = random()
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	484 while u <= 1e-7:
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	485 u = random()
23447 08ccb0f3e2d4 Closes patch 529408 deprecating random.stdgamma(). Raymond Hettinger <python@rcn.com> parents: 23442 diff changeset	486 return -_log(u) * beta
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	487
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	488 else: # alpha is between 0 and 1 (exclusive)
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	489
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	490 # Uses ALGORITHM GS of Statistical Computing - Kennedy & Gentle
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	491
34942 7287b41145ae SF patch #1191489: Simplify logic in random.py Raymond Hettinger <python@rcn.com> parents: 34312 diff changeset	492 while 1:
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	493 u = random()
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	494 b = (_e + alpha)/_e
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	495 p = b*u
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	496 if p <= 1.0:
34942 7287b41145ae SF patch #1191489: Simplify logic in random.py Raymond Hettinger <python@rcn.com> parents: 34312 diff changeset	497 x = p ** (1.0/alpha)
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	498 else:
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	499 x = -_log((b-p)/alpha)
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	500 u1 = random()
34942 7287b41145ae SF patch #1191489: Simplify logic in random.py Raymond Hettinger <python@rcn.com> parents: 34312 diff changeset	501 if p > 1.0:
7287b41145ae SF patch #1191489: Simplify logic in random.py Raymond Hettinger <python@rcn.com> parents: 34312 diff changeset	502 if u1 <= x ** (alpha - 1.0):
7287b41145ae SF patch #1191489: Simplify logic in random.py Raymond Hettinger <python@rcn.com> parents: 34312 diff changeset	503 break
7287b41145ae SF patch #1191489: Simplify logic in random.py Raymond Hettinger <python@rcn.com> parents: 34312 diff changeset	504 elif u1 <= _exp(-x):
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	505 break
23447 08ccb0f3e2d4 Closes patch 529408 deprecating random.stdgamma(). Raymond Hettinger <python@rcn.com> parents: 23442 diff changeset	506 return x * beta
08ccb0f3e2d4 Closes patch 529408 deprecating random.stdgamma(). Raymond Hettinger <python@rcn.com> parents: 23442 diff changeset	507
16265 d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	508 ## -------------------- Gauss (faster alternative) --------------------
1576 695fb494a3a2 Added gauss() (same as normal but twice as fast) and betavariate(); Guido van Rossum <guido@python.org> parents: 1575 diff changeset	509
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	510 def gauss(self, mu, sigma):
23531 a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	511 """Gaussian distribution.
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	512
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	513 mu is the mean, and sigma is the standard deviation. This is
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	514 slightly faster than the normalvariate() function.
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	515
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	516 Not thread-safe without a lock around calls.
23536 0a4c92559a0b Whitespace normalized. Raymond Hettinger <python@rcn.com> parents: 23531 diff changeset	517
23531 a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	518 """
1577 444e349f962f Use float constants directly; cosmetic changes; initialize largest Guido van Rossum <guido@python.org> parents: 1576 diff changeset	519
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	520 # When x and y are two variables from [0, 1), uniformly
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	521 # distributed, then
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	522 #
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	523 # cos(2pix)sqrt(-2log(1-y))
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	524 # sin(2pix)sqrt(-2log(1-y))
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	525 #
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	526 # are two independent variables with normal distribution
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	527 # (mu = 0, sigma = 1).
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	528 # (Lambert Meertens)
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	529 # (corrected version; bug discovered by Mike Miller, fixed by LM)
1577 444e349f962f Use float constants directly; cosmetic changes; initialize largest Guido van Rossum <guido@python.org> parents: 1576 diff changeset	530
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	531 # Multithreading note: When two threads call this function
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	532 # simultaneously, it is possible that they will receive the
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	533 # same return value. The window is very small though. To
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	534 # avoid this, you have to use a lock around all calls. (I
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	535 # didn't want to slow this down in the serial case by using a
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	536 # lock here.)
1577 444e349f962f Use float constants directly; cosmetic changes; initialize largest Guido van Rossum <guido@python.org> parents: 1576 diff changeset	537
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	538 random = self.random
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	539 z = self.gauss_next
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	540 self.gauss_next = None
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	541 if z is None:
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	542 x2pi = random() * TWOPI
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	543 g2rad = _sqrt(-2.0 * _log(1.0 - random()))
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	544 z = _cos(x2pi) * g2rad
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	545 self.gauss_next = _sin(x2pi) * g2rad
1577 444e349f962f Use float constants directly; cosmetic changes; initialize largest Guido van Rossum <guido@python.org> parents: 1576 diff changeset	546
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	547 return mu + z*sigma
1576 695fb494a3a2 Added gauss() (same as normal but twice as fast) and betavariate(); Guido van Rossum <guido@python.org> parents: 1575 diff changeset	548
16265 d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	549 ## -------------------- beta --------------------
16271 7ef2382f6123 SF bug 130030: Claim of bad betavariate algorithm. Tim Peters <tim.peters@gmail.com> parents: 16265 diff changeset	550 ## See
7ef2382f6123 SF bug 130030: Claim of bad betavariate algorithm. Tim Peters <tim.peters@gmail.com> parents: 16265 diff changeset	551 ## http://sourceforge.net/bugs/?func=detailbug&bug_id=130030&group_id=5470
7ef2382f6123 SF bug 130030: Claim of bad betavariate algorithm. Tim Peters <tim.peters@gmail.com> parents: 16265 diff changeset	552 ## for Ivan Frohne's insightful analysis of why the original implementation:
7ef2382f6123 SF bug 130030: Claim of bad betavariate algorithm. Tim Peters <tim.peters@gmail.com> parents: 16265 diff changeset	553 ##
7ef2382f6123 SF bug 130030: Claim of bad betavariate algorithm. Tim Peters <tim.peters@gmail.com> parents: 16265 diff changeset	554 ## def betavariate(self, alpha, beta):
7ef2382f6123 SF bug 130030: Claim of bad betavariate algorithm. Tim Peters <tim.peters@gmail.com> parents: 16265 diff changeset	555 ## # Discrete Event Simulation in C, pp 87-88.
7ef2382f6123 SF bug 130030: Claim of bad betavariate algorithm. Tim Peters <tim.peters@gmail.com> parents: 16265 diff changeset	556 ##
7ef2382f6123 SF bug 130030: Claim of bad betavariate algorithm. Tim Peters <tim.peters@gmail.com> parents: 16265 diff changeset	557 ## y = self.expovariate(alpha)
7ef2382f6123 SF bug 130030: Claim of bad betavariate algorithm. Tim Peters <tim.peters@gmail.com> parents: 16265 diff changeset	558 ## z = self.expovariate(1.0/beta)
7ef2382f6123 SF bug 130030: Claim of bad betavariate algorithm. Tim Peters <tim.peters@gmail.com> parents: 16265 diff changeset	559 ## return z/(y+z)
7ef2382f6123 SF bug 130030: Claim of bad betavariate algorithm. Tim Peters <tim.peters@gmail.com> parents: 16265 diff changeset	560 ##
7ef2382f6123 SF bug 130030: Claim of bad betavariate algorithm. Tim Peters <tim.peters@gmail.com> parents: 16265 diff changeset	561 ## was dead wrong, and how it probably got that way.
1576 695fb494a3a2 Added gauss() (same as normal but twice as fast) and betavariate(); Guido van Rossum <guido@python.org> parents: 1575 diff changeset	562
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	563 def betavariate(self, alpha, beta):
23531 a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	564 """Beta distribution.
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	565
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	566 Conditions on the parameters are alpha > -1 and beta} > -1.
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	567 Returned values range between 0 and 1.
23536 0a4c92559a0b Whitespace normalized. Raymond Hettinger <python@rcn.com> parents: 23531 diff changeset	568
23531 a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	569 """
23536 0a4c92559a0b Whitespace normalized. Raymond Hettinger <python@rcn.com> parents: 23531 diff changeset	570
16271 7ef2382f6123 SF bug 130030: Claim of bad betavariate algorithm. Tim Peters <tim.peters@gmail.com> parents: 16265 diff changeset	571 # This version due to Janne Sinkkonen, and matches all the std
7ef2382f6123 SF bug 130030: Claim of bad betavariate algorithm. Tim Peters <tim.peters@gmail.com> parents: 16265 diff changeset	572 # texts (e.g., Knuth Vol 2 Ed 3 pg 134 "the beta distribution").
7ef2382f6123 SF bug 130030: Claim of bad betavariate algorithm. Tim Peters <tim.peters@gmail.com> parents: 16265 diff changeset	573 y = self.gammavariate(alpha, 1.)
7ef2382f6123 SF bug 130030: Claim of bad betavariate algorithm. Tim Peters <tim.peters@gmail.com> parents: 16265 diff changeset	574 if y == 0:
7ef2382f6123 SF bug 130030: Claim of bad betavariate algorithm. Tim Peters <tim.peters@gmail.com> parents: 16265 diff changeset	575 return 0.0
7ef2382f6123 SF bug 130030: Claim of bad betavariate algorithm. Tim Peters <tim.peters@gmail.com> parents: 16265 diff changeset	576 else:
7ef2382f6123 SF bug 130030: Claim of bad betavariate algorithm. Tim Peters <tim.peters@gmail.com> parents: 16265 diff changeset	577 return y / (y + self.gammavariate(beta, 1.))
1576 695fb494a3a2 Added gauss() (same as normal but twice as fast) and betavariate(); Guido van Rossum <guido@python.org> parents: 1575 diff changeset	578
16265 d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	579 ## -------------------- Pareto --------------------
6698 b73eb4e6face Added Pareto and Weibull distributions, courtesy Jeremy Hylton. Guido van Rossum <guido@python.org> parents: 1618 diff changeset	580
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	581 def paretovariate(self, alpha):
23531 a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	582 """Pareto distribution. alpha is the shape parameter."""
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	583 # Jain, pg. 495
6698 b73eb4e6face Added Pareto and Weibull distributions, courtesy Jeremy Hylton. Guido van Rossum <guido@python.org> parents: 1618 diff changeset	584
27085 90350b5d3397 Correct long standing bugs in the methods for random distributions. Raymond Hettinger <python@rcn.com> parents: 27080 diff changeset	585 u = 1.0 - self.random()
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	586 return 1.0 / pow(u, 1.0/alpha)
6698 b73eb4e6face Added Pareto and Weibull distributions, courtesy Jeremy Hylton. Guido van Rossum <guido@python.org> parents: 1618 diff changeset	587
16265 d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	588 ## -------------------- Weibull --------------------
6698 b73eb4e6face Added Pareto and Weibull distributions, courtesy Jeremy Hylton. Guido van Rossum <guido@python.org> parents: 1618 diff changeset	589
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	590 def weibullvariate(self, alpha, beta):
23531 a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	591 """Weibull distribution.
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	592
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	593 alpha is the scale parameter and beta is the shape parameter.
23536 0a4c92559a0b Whitespace normalized. Raymond Hettinger <python@rcn.com> parents: 23531 diff changeset	594
23531 a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	595 """
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	596 # Jain, pg. 499; bug fix courtesy Bill Arms
11200 bca2d14f3e36 Add Tim Peters' shuffle() algorithm. Guido van Rossum <guido@python.org> parents: 8802 diff changeset	597
27085 90350b5d3397 Correct long standing bugs in the methods for random distributions. Raymond Hettinger <python@rcn.com> parents: 27080 diff changeset	598 u = 1.0 - self.random()
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	599 return alpha * pow(-_log(u), 1.0/beta)
11200 bca2d14f3e36 Add Tim Peters' shuffle() algorithm. Guido van Rossum <guido@python.org> parents: 8802 diff changeset	600
26829 f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	601 ## -------------------- Wichmann-Hill -------------------
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	602
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	603 class WichmannHill(Random):
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	604
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	605 VERSION = 1 # used by getstate/setstate
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	606
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	607 def seed(self, a=None):
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	608 """Initialize internal state from hashable object.
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	609
33481 eacdc29606d8 SF #1027105: HardwareRandom should be renamed OSRandom Raymond Hettinger <python@rcn.com> parents: 33409 diff changeset	610 None or no argument seeds from current time or from an operating
eacdc29606d8 SF #1027105: HardwareRandom should be renamed OSRandom Raymond Hettinger <python@rcn.com> parents: 33409 diff changeset	611 system specific randomness source if available.
26829 f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	612
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	613 If a is not None or an int or long, hash(a) is used instead.
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	614
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	615 If a is an int or long, a is used directly. Distinct values between
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	616 0 and 27814431486575L inclusive are guaranteed to yield distinct
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	617 internal states (this guarantee is specific to the default
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	618 Wichmann-Hill generator).
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	619 """
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	620
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	621 if a is None:
33409 8e23bd3d5b1a Fulfill Martin's request to use try/except rather than a "look before Raymond Hettinger <python@rcn.com> parents: 33399 diff changeset	622 try:
8e23bd3d5b1a Fulfill Martin's request to use try/except rather than a "look before Raymond Hettinger <python@rcn.com> parents: 33399 diff changeset	623 a = long(_hexlify(_urandom(16)), 16)
8e23bd3d5b1a Fulfill Martin's request to use try/except rather than a "look before Raymond Hettinger <python@rcn.com> parents: 33399 diff changeset	624 except NotImplementedError:
33329 97fca735c8da Teach the random module about os.urandom(). Raymond Hettinger <python@rcn.com> parents: 32287 diff changeset	625 import time
97fca735c8da Teach the random module about os.urandom(). Raymond Hettinger <python@rcn.com> parents: 32287 diff changeset	626 a = long(time.time() * 256) # use fractional seconds
26829 f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	627
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	628 if not isinstance(a, (int, long)):
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	629 a = hash(a)
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	630
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	631 a, x = divmod(a, 30268)
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	632 a, y = divmod(a, 30306)
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	633 a, z = divmod(a, 30322)
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	634 self._seed = int(x)+1, int(y)+1, int(z)+1
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	635
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	636 self.gauss_next = None
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	637
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	638 def random(self):
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	639 """Get the next random number in the range [0.0, 1.0)."""
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	640
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	641 # Wichman-Hill random number generator.
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	642 #
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	643 # Wichmann, B. A. & Hill, I. D. (1982)
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	644 # Algorithm AS 183:
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	645 # An efficient and portable pseudo-random number generator
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	646 # Applied Statistics 31 (1982) 188-190
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	647 #
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	648 # see also:
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	649 # Correction to Algorithm AS 183
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	650 # Applied Statistics 33 (1984) 123
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	651 #
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	652 # McLeod, A. I. (1985)
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	653 # A remark on Algorithm AS 183
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	654 # Applied Statistics 34 (1985),198-200
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	655
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	656 # This part is thread-unsafe:
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	657 # BEGIN CRITICAL SECTION
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	658 x, y, z = self._seed
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	659 x = (171 * x) % 30269
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	660 y = (172 * y) % 30307
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	661 z = (170 * z) % 30323
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	662 self._seed = x, y, z
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	663 # END CRITICAL SECTION
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	664
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	665 # Note: on a platform using IEEE-754 double arithmetic, this can
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	666 # never return 0.0 (asserted by Tim; proof too long for a comment).
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	667 return (x/30269.0 + y/30307.0 + z/30323.0) % 1.0
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	668
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	669 def getstate(self):
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	670 """Return internal state; can be passed to setstate() later."""
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	671 return self.VERSION, self._seed, self.gauss_next
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	672
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	673 def setstate(self, state):
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	674 """Restore internal state from object returned by getstate()."""
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	675 version = state[0]
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	676 if version == 1:
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	677 version, self._seed, self.gauss_next = state
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	678 else:
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	679 raise ValueError("state with version %s passed to "
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	680 "Random.setstate() of version %s" %
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	681 (version, self.VERSION))
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	682
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	683 def jumpahead(self, n):
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	684 """Act as if n calls to random() were made, but quickly.
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	685
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	686 n is an int, greater than or equal to 0.
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	687
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	688 Example use: If you have 2 threads and know that each will
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	689 consume no more than a million random numbers, create two Random
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	690 objects r1 and r2, then do
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	691 r2.setstate(r1.getstate())
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	692 r2.jumpahead(1000000)
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	693 Then r1 and r2 will use guaranteed-disjoint segments of the full
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	694 period.
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	695 """
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	696
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	697 if not n >= 0:
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	698 raise ValueError("n must be >= 0")
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	699 x, y, z = self._seed
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	700 x = int(x * pow(171, n, 30269)) % 30269
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	701 y = int(y * pow(172, n, 30307)) % 30307
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	702 z = int(z * pow(170, n, 30323)) % 30323
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	703 self._seed = x, y, z
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	704
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	705 def __whseed(self, x=0, y=0, z=0):
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	706 """Set the Wichmann-Hill seed from (x, y, z).
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	707
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	708 These must be integers in the range [0, 256).
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	709 """
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	710
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	711 if not type(x) == type(y) == type(z) == int:
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	712 raise TypeError('seeds must be integers')
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	713 if not (0 <= x < 256 and 0 <= y < 256 and 0 <= z < 256):
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	714 raise ValueError('seeds must be in range(0, 256)')
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	715 if 0 == x == y == z:
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	716 # Initialize from current time
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	717 import time
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	718 t = long(time.time() * 256)
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	719 t = int((t&0xffffff) ^ (t>>24))
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	720 t, x = divmod(t, 256)
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	721 t, y = divmod(t, 256)
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	722 t, z = divmod(t, 256)
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	723 # Zero is a poor seed, so substitute 1
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	724 self._seed = (x or 1, y or 1, z or 1)
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	725
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	726 self.gauss_next = None
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	727
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	728 def whseed(self, a=None):
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	729 """Seed from hashable object's hash code.
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	730
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	731 None or no argument seeds from current time. It is not guaranteed
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	732 that objects with distinct hash codes lead to distinct internal
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	733 states.
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	734
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	735 This is obsolete, provided for compatibility with the seed routine
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	736 used prior to Python 2.1. Use the .seed() method instead.
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	737 """
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	738
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	739 if a is None:
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	740 self.__whseed()
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	741 return
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	742 a = hash(a)
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	743 a, x = divmod(a, 256)
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	744 a, y = divmod(a, 256)
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	745 a, z = divmod(a, 256)
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	746 x = (x + a) % 256 or 1
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	747 y = (y + a) % 256 or 1
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	748 z = (z + a) % 256 or 1
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	749 self.__whseed(x, y, z)
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	750
33481 eacdc29606d8 SF #1027105: HardwareRandom should be renamed OSRandom Raymond Hettinger <python@rcn.com> parents: 33409 diff changeset	751 ## --------------- Operating System Random Source ------------------
33329 97fca735c8da Teach the random module about os.urandom(). Raymond Hettinger <python@rcn.com> parents: 32287 diff changeset	752
33481 eacdc29606d8 SF #1027105: HardwareRandom should be renamed OSRandom Raymond Hettinger <python@rcn.com> parents: 33409 diff changeset	753 class SystemRandom(Random):
eacdc29606d8 SF #1027105: HardwareRandom should be renamed OSRandom Raymond Hettinger <python@rcn.com> parents: 33409 diff changeset	754 """Alternate random number generator using sources provided
eacdc29606d8 SF #1027105: HardwareRandom should be renamed OSRandom Raymond Hettinger <python@rcn.com> parents: 33409 diff changeset	755 by the operating system (such as /dev/urandom on Unix or
eacdc29606d8 SF #1027105: HardwareRandom should be renamed OSRandom Raymond Hettinger <python@rcn.com> parents: 33409 diff changeset	756 CryptGenRandom on Windows).
33329 97fca735c8da Teach the random module about os.urandom(). Raymond Hettinger <python@rcn.com> parents: 32287 diff changeset	757
97fca735c8da Teach the random module about os.urandom(). Raymond Hettinger <python@rcn.com> parents: 32287 diff changeset	758 Not available on all systems (see os.urandom() for details).
97fca735c8da Teach the random module about os.urandom(). Raymond Hettinger <python@rcn.com> parents: 32287 diff changeset	759 """
97fca735c8da Teach the random module about os.urandom(). Raymond Hettinger <python@rcn.com> parents: 32287 diff changeset	760
97fca735c8da Teach the random module about os.urandom(). Raymond Hettinger <python@rcn.com> parents: 32287 diff changeset	761 def random(self):
97fca735c8da Teach the random module about os.urandom(). Raymond Hettinger <python@rcn.com> parents: 32287 diff changeset	762 """Get the next random number in the range [0.0, 1.0)."""
33350 c44f083465f9 HardwareRandom: Go back to multiplying by 2*-BPF instead of using Tim Peters <tim.peters@gmail.com>* parents: 33349 diff changeset	763 return (long(_hexlify(_urandom(7)), 16) >> 3) * RECIP_BPF
33329 97fca735c8da Teach the random module about os.urandom(). Raymond Hettinger <python@rcn.com> parents: 32287 diff changeset	764
97fca735c8da Teach the random module about os.urandom(). Raymond Hettinger <python@rcn.com> parents: 32287 diff changeset	765 def getrandbits(self, k):
97fca735c8da Teach the random module about os.urandom(). Raymond Hettinger <python@rcn.com> parents: 32287 diff changeset	766 """getrandbits(k) -> x. Generates a long int with k random bits."""
97fca735c8da Teach the random module about os.urandom(). Raymond Hettinger <python@rcn.com> parents: 32287 diff changeset	767 if k <= 0:
97fca735c8da Teach the random module about os.urandom(). Raymond Hettinger <python@rcn.com> parents: 32287 diff changeset	768 raise ValueError('number of bits must be greater than zero')
97fca735c8da Teach the random module about os.urandom(). Raymond Hettinger <python@rcn.com> parents: 32287 diff changeset	769 if k != int(k):
97fca735c8da Teach the random module about os.urandom(). Raymond Hettinger <python@rcn.com> parents: 32287 diff changeset	770 raise TypeError('number of bits should be an integer')
97fca735c8da Teach the random module about os.urandom(). Raymond Hettinger <python@rcn.com> parents: 32287 diff changeset	771 bytes = (k + 7) // 8 # bits / 8 and rounded up
97fca735c8da Teach the random module about os.urandom(). Raymond Hettinger <python@rcn.com> parents: 32287 diff changeset	772 x = long(_hexlify(_urandom(bytes)), 16)
97fca735c8da Teach the random module about os.urandom(). Raymond Hettinger <python@rcn.com> parents: 32287 diff changeset	773 return x >> (bytes * 8 - k) # trim excess bits
97fca735c8da Teach the random module about os.urandom(). Raymond Hettinger <python@rcn.com> parents: 32287 diff changeset	774
97fca735c8da Teach the random module about os.urandom(). Raymond Hettinger <python@rcn.com> parents: 32287 diff changeset	775 def _stub(self, args, *kwds):
33481 eacdc29606d8 SF #1027105: HardwareRandom should be renamed OSRandom Raymond Hettinger <python@rcn.com> parents: 33409 diff changeset	776 "Stub method. Not used for a system random number generator."
33329 97fca735c8da Teach the random module about os.urandom(). Raymond Hettinger <python@rcn.com> parents: 32287 diff changeset	777 return None
97fca735c8da Teach the random module about os.urandom(). Raymond Hettinger <python@rcn.com> parents: 32287 diff changeset	778 seed = jumpahead = _stub
97fca735c8da Teach the random module about os.urandom(). Raymond Hettinger <python@rcn.com> parents: 32287 diff changeset	779
97fca735c8da Teach the random module about os.urandom(). Raymond Hettinger <python@rcn.com> parents: 32287 diff changeset	780 def _notimplemented(self, args, *kwds):
33481 eacdc29606d8 SF #1027105: HardwareRandom should be renamed OSRandom Raymond Hettinger <python@rcn.com> parents: 33409 diff changeset	781 "Method should not be called for a system random number generator."
eacdc29606d8 SF #1027105: HardwareRandom should be renamed OSRandom Raymond Hettinger <python@rcn.com> parents: 33409 diff changeset	782 raise NotImplementedError('System entropy source does not have state.')
33329 97fca735c8da Teach the random module about os.urandom(). Raymond Hettinger <python@rcn.com> parents: 32287 diff changeset	783 getstate = setstate = _notimplemented
97fca735c8da Teach the random module about os.urandom(). Raymond Hettinger <python@rcn.com> parents: 32287 diff changeset	784
16265 d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	785 ## -------------------- test program --------------------
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	786
30243 53a322c6de52 Eliminate unnecessary eval() in tests Raymond Hettinger <python@rcn.com> parents: 30114 diff changeset	787 def _test_generator(n, func, args):
15871 62aeefa01fdd Whitespace normalization. Tim Peters <tim.peters@gmail.com> parents: 14617 diff changeset	788 import time
30243 53a322c6de52 Eliminate unnecessary eval() in tests Raymond Hettinger <python@rcn.com> parents: 30114 diff changeset	789 print n, 'times', func.__name__
29250 34609fa35b11 'sum' is no longer a good variable name. Use 'total' instead. Raymond Hettinger <python@rcn.com> parents: 27279 diff changeset	790 total = 0.0
15871 62aeefa01fdd Whitespace normalization. Tim Peters <tim.peters@gmail.com> parents: 14617 diff changeset	791 sqsum = 0.0
62aeefa01fdd Whitespace normalization. Tim Peters <tim.peters@gmail.com> parents: 14617 diff changeset	792 smallest = 1e10
62aeefa01fdd Whitespace normalization. Tim Peters <tim.peters@gmail.com> parents: 14617 diff changeset	793 largest = -1e10
62aeefa01fdd Whitespace normalization. Tim Peters <tim.peters@gmail.com> parents: 14617 diff changeset	794 t0 = time.time()
62aeefa01fdd Whitespace normalization. Tim Peters <tim.peters@gmail.com> parents: 14617 diff changeset	795 for i in range(n):
30243 53a322c6de52 Eliminate unnecessary eval() in tests Raymond Hettinger <python@rcn.com> parents: 30114 diff changeset	796 x = func(*args)
29250 34609fa35b11 'sum' is no longer a good variable name. Use 'total' instead. Raymond Hettinger <python@rcn.com> parents: 27279 diff changeset	797 total += x
15871 62aeefa01fdd Whitespace normalization. Tim Peters <tim.peters@gmail.com> parents: 14617 diff changeset	798 sqsum = sqsum + x*x
62aeefa01fdd Whitespace normalization. Tim Peters <tim.peters@gmail.com> parents: 14617 diff changeset	799 smallest = min(x, smallest)
62aeefa01fdd Whitespace normalization. Tim Peters <tim.peters@gmail.com> parents: 14617 diff changeset	800 largest = max(x, largest)
62aeefa01fdd Whitespace normalization. Tim Peters <tim.peters@gmail.com> parents: 14617 diff changeset	801 t1 = time.time()
62aeefa01fdd Whitespace normalization. Tim Peters <tim.peters@gmail.com> parents: 14617 diff changeset	802 print round(t1-t0, 3), 'sec,',
29250 34609fa35b11 'sum' is no longer a good variable name. Use 'total' instead. Raymond Hettinger <python@rcn.com> parents: 27279 diff changeset	803 avg = total/n
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	804 stddev = _sqrt(sqsum/n - avg*avg)
15871 62aeefa01fdd Whitespace normalization. Tim Peters <tim.peters@gmail.com> parents: 14617 diff changeset	805 print 'avg %g, stddev %g, min %g, max %g' % \
62aeefa01fdd Whitespace normalization. Tim Peters <tim.peters@gmail.com> parents: 14617 diff changeset	806 (avg, stddev, smallest, largest)
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	807
26155 8ceb455f5541 SF patch 629637: Add sample(population, k) method to the random module. Raymond Hettinger <python@rcn.com> parents: 24861 diff changeset	808
8ceb455f5541 SF patch 629637: Add sample(population, k) method to the random module. Raymond Hettinger <python@rcn.com> parents: 24861 diff changeset	809 def _test(N=2000):
30243 53a322c6de52 Eliminate unnecessary eval() in tests Raymond Hettinger <python@rcn.com> parents: 30114 diff changeset	810 _test_generator(N, random, ())
53a322c6de52 Eliminate unnecessary eval() in tests Raymond Hettinger <python@rcn.com> parents: 30114 diff changeset	811 _test_generator(N, normalvariate, (0.0, 1.0))
53a322c6de52 Eliminate unnecessary eval() in tests Raymond Hettinger <python@rcn.com> parents: 30114 diff changeset	812 _test_generator(N, lognormvariate, (0.0, 1.0))
53a322c6de52 Eliminate unnecessary eval() in tests Raymond Hettinger <python@rcn.com> parents: 30114 diff changeset	813 _test_generator(N, vonmisesvariate, (0.0, 1.0))
53a322c6de52 Eliminate unnecessary eval() in tests Raymond Hettinger <python@rcn.com> parents: 30114 diff changeset	814 _test_generator(N, gammavariate, (0.01, 1.0))
53a322c6de52 Eliminate unnecessary eval() in tests Raymond Hettinger <python@rcn.com> parents: 30114 diff changeset	815 _test_generator(N, gammavariate, (0.1, 1.0))
53a322c6de52 Eliminate unnecessary eval() in tests Raymond Hettinger <python@rcn.com> parents: 30114 diff changeset	816 _test_generator(N, gammavariate, (0.1, 2.0))
53a322c6de52 Eliminate unnecessary eval() in tests Raymond Hettinger <python@rcn.com> parents: 30114 diff changeset	817 _test_generator(N, gammavariate, (0.5, 1.0))
53a322c6de52 Eliminate unnecessary eval() in tests Raymond Hettinger <python@rcn.com> parents: 30114 diff changeset	818 _test_generator(N, gammavariate, (0.9, 1.0))
53a322c6de52 Eliminate unnecessary eval() in tests Raymond Hettinger <python@rcn.com> parents: 30114 diff changeset	819 _test_generator(N, gammavariate, (1.0, 1.0))
53a322c6de52 Eliminate unnecessary eval() in tests Raymond Hettinger <python@rcn.com> parents: 30114 diff changeset	820 _test_generator(N, gammavariate, (2.0, 1.0))
53a322c6de52 Eliminate unnecessary eval() in tests Raymond Hettinger <python@rcn.com> parents: 30114 diff changeset	821 _test_generator(N, gammavariate, (20.0, 1.0))
53a322c6de52 Eliminate unnecessary eval() in tests Raymond Hettinger <python@rcn.com> parents: 30114 diff changeset	822 _test_generator(N, gammavariate, (200.0, 1.0))
53a322c6de52 Eliminate unnecessary eval() in tests Raymond Hettinger <python@rcn.com> parents: 30114 diff changeset	823 _test_generator(N, gauss, (0.0, 1.0))
53a322c6de52 Eliminate unnecessary eval() in tests Raymond Hettinger <python@rcn.com> parents: 30114 diff changeset	824 _test_generator(N, betavariate, (3.0, 3.0))
16265 d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	825
16292 0501c2a10315 New comment block to Clarify a subtlety. Tim Peters <tim.peters@gmail.com> parents: 16272 diff changeset	826 # Create one instance, seeded from current time, and export its methods
26829 f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	827 # as module-level functions. The functions share state across all uses
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	828 #(both in the user's code and in the Python libraries), but that's fine
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	829 # for most programs and is easier for the casual user than making them
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	830 # instantiate their own Random() instance.
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	831
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	832 _inst = Random()
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	833 seed = _inst.seed
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	834 random = _inst.random
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	835 uniform = _inst.uniform
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	836 randint = _inst.randint
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	837 choice = _inst.choice
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	838 randrange = _inst.randrange
26155 8ceb455f5541 SF patch 629637: Add sample(population, k) method to the random module. Raymond Hettinger <python@rcn.com> parents: 24861 diff changeset	839 sample = _inst.sample
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	840 shuffle = _inst.shuffle
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	841 normalvariate = _inst.normalvariate
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	842 lognormvariate = _inst.lognormvariate
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	843 expovariate = _inst.expovariate
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	844 vonmisesvariate = _inst.vonmisesvariate
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	845 gammavariate = _inst.gammavariate
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	846 gauss = _inst.gauss
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	847 betavariate = _inst.betavariate
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	848 paretovariate = _inst.paretovariate
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	849 weibullvariate = _inst.weibullvariate
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	850 getstate = _inst.getstate
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	851 setstate = _inst.setstate
16243 9fd96e2455b6 Fix bugs introduced by rewrite (in particular, time-based initialization Tim Peters <tim.peters@gmail.com> parents: 16242 diff changeset	852 jumpahead = _inst.jumpahead
30649 8841d34a2c37 SF bug #812202: randint is always even Raymond Hettinger <python@rcn.com> parents: 30346 diff changeset	853 getrandbits = _inst.getrandbits
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	854
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	855 if __name__ == '__main__':
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	856 _test()

Mercurial > cpython-lru_cache-weakref

annotate Lib/random.py @ 37850:ebe59cd18273