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

annotate Lib/random.py @ 71285:8bc9dbc61ba6 3.2

Issue #12326: document the recommended idiom for checking sys.platform on Unix systems. Also, point to the various alternatives.

author	Antoine Pitrou <solipsis@pitrou.net>
date	Sat, 09 Jul 2011 15:54:23 +0200
parents	9216e0a5d950
children	3fdc5a75d6e1 67ea5cebca1c

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
46034 0a485593ae1c Merged revisions 61724-61725,61731-61735,61737,61739,61741,61743-61744,61753,61761,61765-61767,61769,61773,61776-61778,61780-61783,61788,61793,61796,61807,61813 via svnmerge from Christian Heimes <christian@cheimes.de> parents: 44665 diff changeset	16 triangular
11707 6f4146846337 The third and final doc-string sweep by Ka-Ping Yee. Guido van Rossum <guido@python.org> parents: 11200 diff changeset	17 normal (Gaussian)
6f4146846337 The third and final doc-string sweep by Ka-Ping Yee. Guido van Rossum <guido@python.org> parents: 11200 diff changeset	18 lognormal
6f4146846337 The third and final doc-string sweep by Ka-Ping Yee. Guido van Rossum <guido@python.org> parents: 11200 diff changeset	19 negative exponential
6f4146846337 The third and final doc-string sweep by Ka-Ping Yee. Guido van Rossum <guido@python.org> parents: 11200 diff changeset	20 gamma
6f4146846337 The third and final doc-string sweep by Ka-Ping Yee. Guido van Rossum <guido@python.org> parents: 11200 diff changeset	21 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	22 pareto
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	23 Weibull
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	24
11707 6f4146846337 The third and final doc-string sweep by Ka-Ping Yee. Guido van Rossum <guido@python.org> parents: 11200 diff changeset	25 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	26 ---------------------------------------------
6f4146846337 The third and final doc-string sweep by Ka-Ping Yee. Guido van Rossum <guido@python.org> parents: 11200 diff changeset	27 circular uniform
6f4146846337 The third and final doc-string sweep by Ka-Ping Yee. Guido van Rossum <guido@python.org> parents: 11200 diff changeset	28 von Mises
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	29
26829 f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	30 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	31
26829 f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	32 * The period is 2**19937-1.
39442 654c380cf8b9 Merged revisions 46753-51188 via svnmerge from Thomas Wouters <thomas@python.org> parents: 37879 diff changeset	33 * It is one of the most extensively tested generators in existence.
654c380cf8b9 Merged revisions 46753-51188 via svnmerge from Thomas Wouters <thomas@python.org> parents: 37879 diff changeset	34 * The random() method is implemented in C, executes in a single Python step,
654c380cf8b9 Merged revisions 46753-51188 via svnmerge from Thomas Wouters <thomas@python.org> parents: 37879 diff changeset	35 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	36
11707 6f4146846337 The third and final doc-string sweep by Ka-Ping Yee. Guido van Rossum <guido@python.org> parents: 11200 diff changeset	37 """
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	38
46034 0a485593ae1c Merged revisions 61724-61725,61731-61735,61737,61739,61741,61743-61744,61753,61761,61765-61767,61769,61773,61776-61778,61780-61783,61788,61793,61796,61807,61813 via svnmerge from Christian Heimes <christian@cheimes.de> parents: 44665 diff changeset	39 from __future__ import division
30649 8841d34a2c37 SF bug #812202: randint is always even Raymond Hettinger <python@rcn.com> parents: 30346 diff changeset	40 from warnings import warn as _warn
8841d34a2c37 SF bug #812202: randint is always even Raymond Hettinger <python@rcn.com> parents: 30346 diff changeset	41 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	42 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	43 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	44 from os import urandom as _urandom
69859 e2f7db1255df Sync-up minor code edits with the default branch. Raymond Hettinger <python@rcn.com> parents: 69857 diff changeset	45 from collections import Set as _Set, Sequence as _Sequence
66786 f4f56efa2870 Update whatsnew. Salt the random number seed. Raymond Hettinger <python@rcn.com> parents: 64569 diff changeset	46 from hashlib import sha512 as _sha512
8455 af9273b1073a Make gauss() semi-thread-safe. It can still give duplicate results, Guido van Rossum <guido@python.org> parents: 8393 diff changeset	47
26155 8ceb455f5541 SF patch 629637: Add sample(population, k) method to the random module. Raymond Hettinger <python@rcn.com> parents: 24861 diff changeset	48 __all__ = ["Random","seed","random","uniform","randint","choice","sample",
16613 f68dbffff927 bunch more __all__ lists Skip Montanaro <skip@pobox.com> parents: 16386 diff changeset	49 "randrange","shuffle","normalvariate","lognormvariate",
46034 0a485593ae1c Merged revisions 61724-61725,61731-61735,61737,61739,61741,61743-61744,61753,61761,61765-61767,61769,61773,61776-61778,61780-61783,61788,61793,61796,61807,61813 via svnmerge from Christian Heimes <christian@cheimes.de> parents: 44665 diff changeset	50 "expovariate","vonmisesvariate","gammavariate","triangular",
30068 171814f5dcc6 Removed deprecated functions Raymond Hettinger <python@rcn.com> parents: 29586 diff changeset	51 "gauss","betavariate","paretovariate","weibullvariate",
44662 c25760c21397 Remove defunct parts of the random module Raymond Hettinger <python@rcn.com> parents: 44129 diff changeset	52 "getstate","setstate", "getrandbits",
33481 eacdc29606d8 SF #1027105: HardwareRandom should be renamed OSRandom Raymond Hettinger <python@rcn.com> parents: 33409 diff changeset	53 "SystemRandom"]
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	54
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	55 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	56 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	57 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	58 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	59 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	60 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	61
33329 97fca735c8da Teach the random module about os.urandom(). Raymond Hettinger <python@rcn.com> parents: 32287 diff changeset	62
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	63 # 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	64 # 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	65 # 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	66
27131 e87d590a5de1 Much clearer when super() is used. Raymond Hettinger <python@rcn.com> parents: 27094 diff changeset	67 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	68
27131 e87d590a5de1 Much clearer when super() is used. Raymond Hettinger <python@rcn.com> parents: 27094 diff changeset	69 class Random(_random.Random):
23531 a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	70 """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	71
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	72 Used to instantiate instances of Random to get generators that don't
44662 c25760c21397 Remove defunct parts of the random module Raymond Hettinger <python@rcn.com> parents: 44129 diff changeset	73 share state.
23531 a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	74
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	75 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	76 generator of your own devising: in that case, override the following
44662 c25760c21397 Remove defunct parts of the random module Raymond Hettinger <python@rcn.com> parents: 44129 diff changeset	77 methods: random(), seed(), getstate(), and setstate().
48596 13b2e11f3cf5 Merged revisions 65259,65263,65296,65307,65321 via svnmerge from Benjamin Peterson <benjamin@python.org> parents: 46034 diff changeset	78 Optionally, implement a getrandbits() method so that randrange()
30649 8841d34a2c37 SF bug #812202: randint is always even Raymond Hettinger <python@rcn.com> parents: 30346 diff changeset	79 can cover arbitrarily large ranges.
23536 0a4c92559a0b Whitespace normalized. Raymond Hettinger <python@rcn.com> parents: 23531 diff changeset	80
23531 a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	81 """
8393 7669ddf0e7d4 Add Interfaces to replace remaining needs for importing whrandom. Guido van Rossum <guido@python.org> parents: 7881 diff changeset	82
44129 b637349336fd Merged revisions 59275-59303 via svnmerge from Christian Heimes <christian@cheimes.de> parents: 43020 diff changeset	83 VERSION = 3 # 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	84
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	85 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	86 """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	87
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 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	89 """
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
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 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	92 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	93
64510 65642f085c55 Document which part of the random module module are guaranteed. Raymond Hettinger <python@rcn.com> parents: 57584 diff changeset	94 def seed(self, a=None, version=2):
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	95 """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	96
33481 eacdc29606d8 SF #1027105: HardwareRandom should be renamed OSRandom Raymond Hettinger <python@rcn.com> parents: 33409 diff changeset	97 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	98 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	99
64567 b1865ca7b65c * Remove dependency on binascii.hexlify by using int.from_bytes(). Raymond Hettinger <python@rcn.com> parents: 64553 diff changeset	100 For version 2 (the default), all of the bits are used if a is a str,
b1865ca7b65c * Remove dependency on binascii.hexlify by using int.from_bytes(). Raymond Hettinger <python@rcn.com> parents: 64553 diff changeset	101 bytes, or bytearray. For version 1, the hash() of a is used instead.
64510 65642f085c55 Document which part of the random module module are guaranteed. Raymond Hettinger <python@rcn.com> parents: 57584 diff changeset	102
64567 b1865ca7b65c * Remove dependency on binascii.hexlify by using int.from_bytes(). Raymond Hettinger <python@rcn.com> parents: 64553 diff changeset	103 If a is an int, all bits are used.
64510 65642f085c55 Document which part of the random module module are guaranteed. Raymond Hettinger <python@rcn.com> parents: 57584 diff changeset	104
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:
64567 b1865ca7b65c * Remove dependency on binascii.hexlify by using int.from_bytes(). Raymond Hettinger <python@rcn.com> parents: 64553 diff changeset	109 a = int.from_bytes(_urandom(32), 'big')
33409 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
40644 1c26505c1de6 Rip out 'long' and 'L'-suffixed integer literals. Guido van Rossum <guido@python.org> parents: 40582 diff changeset	112 a = int(time.time() * 256) # use fractional seconds
33329 97fca735c8da Teach the random module about os.urandom(). Raymond Hettinger <python@rcn.com> parents: 32287 diff changeset	113
66786 f4f56efa2870 Update whatsnew. Salt the random number seed. Raymond Hettinger <python@rcn.com> parents: 64569 diff changeset	114 if version == 2:
f4f56efa2870 Update whatsnew. Salt the random number seed. Raymond Hettinger <python@rcn.com> parents: 64569 diff changeset	115 if isinstance(a, (str, bytes, bytearray)):
f4f56efa2870 Update whatsnew. Salt the random number seed. Raymond Hettinger <python@rcn.com> parents: 64569 diff changeset	116 if isinstance(a, str):
69857 1a56775c6e54 Avoid codec spelling issues by just using the utf-8 default. Raymond Hettinger <python@rcn.com> parents: 69363 diff changeset	117 a = a.encode()
66786 f4f56efa2870 Update whatsnew. Salt the random number seed. Raymond Hettinger <python@rcn.com> parents: 64569 diff changeset	118 a += _sha512(a).digest()
f4f56efa2870 Update whatsnew. Salt the random number seed. Raymond Hettinger <python@rcn.com> parents: 64569 diff changeset	119 a = int.from_bytes(a, 'big')
64510 65642f085c55 Document which part of the random module module are guaranteed. Raymond Hettinger <python@rcn.com> parents: 57584 diff changeset	120
42084 229c28cb9afb Merged revisions 55817-55961 via svnmerge from Guido van Rossum <guido@python.org> parents: 41642 diff changeset	121 super().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	122 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	123
16265 d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	124 def getstate(self):
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	125 """Return internal state; can be passed to setstate() later."""
42084 229c28cb9afb Merged revisions 55817-55961 via svnmerge from Guido van Rossum <guido@python.org> parents: 41642 diff changeset	126 return self.VERSION, super().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	127
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	128 def setstate(self, state):
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	129 """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	130 version = state[0]
44129 b637349336fd Merged revisions 59275-59303 via svnmerge from Christian Heimes <christian@cheimes.de> parents: 43020 diff changeset	131 if version == 3:
26829 f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the Raymond Hettinger <python@rcn.com> parents: 26564 diff changeset	132 version, internalstate, self.gauss_next = state
42084 229c28cb9afb Merged revisions 55817-55961 via svnmerge from Guido van Rossum <guido@python.org> parents: 41642 diff changeset	133 super().setstate(internalstate)
44129 b637349336fd Merged revisions 59275-59303 via svnmerge from Christian Heimes <christian@cheimes.de> parents: 43020 diff changeset	134 elif version == 2:
b637349336fd Merged revisions 59275-59303 via svnmerge from Christian Heimes <christian@cheimes.de> parents: 43020 diff changeset	135 version, internalstate, self.gauss_next = state
b637349336fd Merged revisions 59275-59303 via svnmerge from Christian Heimes <christian@cheimes.de> parents: 43020 diff changeset	136 # In version 2, the state was saved as signed ints, which causes
b637349336fd Merged revisions 59275-59303 via svnmerge from Christian Heimes <christian@cheimes.de> parents: 43020 diff changeset	137 # inconsistencies between 32/64-bit systems. The state is
b637349336fd Merged revisions 59275-59303 via svnmerge from Christian Heimes <christian@cheimes.de> parents: 43020 diff changeset	138 # really unsigned 32-bit ints, so we convert negative ints from
b637349336fd Merged revisions 59275-59303 via svnmerge from Christian Heimes <christian@cheimes.de> parents: 43020 diff changeset	139 # version 2 to positive longs for version 3.
b637349336fd Merged revisions 59275-59303 via svnmerge from Christian Heimes <christian@cheimes.de> parents: 43020 diff changeset	140 try:
64523 6095ea9dcff4 Fix test that depends on a particular implementation of random.choice(). Raymond Hettinger <python@rcn.com> parents: 64517 diff changeset	141 internalstate = tuple(x % (2**32) for x in internalstate)
44129 b637349336fd Merged revisions 59275-59303 via svnmerge from Christian Heimes <christian@cheimes.de> parents: 43020 diff changeset	142 except ValueError as e:
b637349336fd Merged revisions 59275-59303 via svnmerge from Christian Heimes <christian@cheimes.de> parents: 43020 diff changeset	143 raise TypeError from e
64567 b1865ca7b65c * Remove dependency on binascii.hexlify by using int.from_bytes(). Raymond Hettinger <python@rcn.com> parents: 64553 diff changeset	144 super().setstate(internalstate)
16265 d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	145 else:
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	146 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	147 "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	148 (version, self.VERSION))
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	149
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	150 ## ---- 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	151 ## ---- 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	152
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	153 ## -------------------- pickle support -------------------
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	154
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	155 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	156 return self.getstate()
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	157
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	158 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	159 self.setstate(state)
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	160
29586 8b163370372d SF bug #759889: Pickling of Random is broken Raymond Hettinger <python@rcn.com> parents: 29539 diff changeset	161 def __reduce__(self):
8b163370372d SF bug #759889: Pickling of Random is broken Raymond Hettinger <python@rcn.com> parents: 29539 diff changeset	162 return self.__class__, (), self.getstate()
8b163370372d SF bug #759889: Pickling of Random is broken Raymond Hettinger <python@rcn.com> parents: 29539 diff changeset	163
16265 d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	164 ## -------------------- integer methods -------------------
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	165
64512 c2f8418a0e14 Issues #7889, #9025 and #9379: Improvements to the random module. Raymond Hettinger <python@rcn.com> parents: 64511 diff changeset	166 def randrange(self, start, stop=None, step=1, int=int):
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	167 """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	168
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	169 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	170 endpoint; in Python this is usually not what you want.
64511 11ba6397e3a4 Minor code cleanup Raymond Hettinger <python@rcn.com> parents: 64510 diff changeset	171
64516 6ba20b9039ae Small clean-ups. Raymond Hettinger <python@rcn.com> parents: 64512 diff changeset	172 Do not supply the 'int' argument.
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	173 """
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	174
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	175 # 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	176 # 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	177 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	178 if istart != start:
43020 907a45df1295 Raise statement normalization in Lib/. Collin Winter <collinw@gmail.com> parents: 42084 diff changeset	179 raise ValueError("non-integer arg 1 for randrange()")
64511 11ba6397e3a4 Minor code cleanup Raymond Hettinger <python@rcn.com> parents: 64510 diff changeset	180 if stop is 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	181 if istart > 0:
64512 c2f8418a0e14 Issues #7889, #9025 and #9379: Improvements to the random module. Raymond Hettinger <python@rcn.com> parents: 64511 diff changeset	182 return self._randbelow(istart)
43020 907a45df1295 Raise statement normalization in Lib/. Collin Winter <collinw@gmail.com> parents: 42084 diff changeset	183 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	184
4e795fe9f54b SF bug 594996: OverflowError in random.randrange Tim Peters <tim.peters@gmail.com> parents: 23536 diff changeset	185 # 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	186 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	187 if istop != stop:
43020 907a45df1295 Raise statement normalization in Lib/. Collin Winter <collinw@gmail.com> parents: 42084 diff changeset	188 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	189 width = istop - istart
8841d34a2c37 SF bug #812202: randint is always even Raymond Hettinger <python@rcn.com> parents: 30346 diff changeset	190 if step == 1 and width > 0:
64516 6ba20b9039ae Small clean-ups. Raymond Hettinger <python@rcn.com> parents: 64512 diff changeset	191 return istart + self._randbelow(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	192 if step == 1:
43020 907a45df1295 Raise statement normalization in Lib/. Collin Winter <collinw@gmail.com> parents: 42084 diff changeset	193 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	194
4e795fe9f54b SF bug 594996: OverflowError in random.randrange Tim Peters <tim.peters@gmail.com> parents: 23536 diff changeset	195 # 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	196 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	197 if istep != step:
43020 907a45df1295 Raise statement normalization in Lib/. Collin Winter <collinw@gmail.com> parents: 42084 diff changeset	198 raise ValueError("non-integer step for randrange()")
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	199 if istep > 0:
33597 355b15e4a4da Use floor division operator. Raymond Hettinger <python@rcn.com> parents: 33481 diff changeset	200 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	201 elif istep < 0:
33597 355b15e4a4da Use floor division operator. Raymond Hettinger <python@rcn.com> parents: 33481 diff changeset	202 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	203 else:
43020 907a45df1295 Raise statement normalization in Lib/. Collin Winter <collinw@gmail.com> parents: 42084 diff changeset	204 raise ValueError("zero step for randrange()")
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	205
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 if n <= 0:
43020 907a45df1295 Raise statement normalization in Lib/. Collin Winter <collinw@gmail.com> parents: 42084 diff changeset	207 raise ValueError("empty range for randrange()")
30649 8841d34a2c37 SF bug #812202: randint is always even Raymond Hettinger <python@rcn.com> parents: 30346 diff changeset	208
64512 c2f8418a0e14 Issues #7889, #9025 and #9379: Improvements to the random module. Raymond Hettinger <python@rcn.com> parents: 64511 diff changeset	209 return istart + istep*self._randbelow(n)
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	210
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	211 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	212 """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	213 """
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 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	216
64553 d5331712b509 In the case where only a user supplied random() method is available, Raymond Hettinger <python@rcn.com> parents: 64532 diff changeset	217 def _randbelow(self, n, int=int, maxsize=1<<BPF, type=type,
64531 770c3ec05685 Minor refactoring and cleanup. Extend looping randrange() technique to subclasses. Raymond Hettinger <python@rcn.com> parents: 64523 diff changeset	218 Method=_MethodType, BuiltinMethod=_BuiltinMethodType):
64553 d5331712b509 In the case where only a user supplied random() method is available, Raymond Hettinger <python@rcn.com> parents: 64532 diff changeset	219 "Return a random int in the range [0,n). Raises ValueError if n==0."
30649 8841d34a2c37 SF bug #812202: randint is always even Raymond Hettinger <python@rcn.com> parents: 30346 diff changeset	220
64516 6ba20b9039ae Small clean-ups. Raymond Hettinger <python@rcn.com> parents: 64512 diff changeset	221 getrandbits = self.getrandbits
6ba20b9039ae Small clean-ups. Raymond Hettinger <python@rcn.com> parents: 64512 diff changeset	222 # Only call self.getrandbits if the original random() builtin method
6ba20b9039ae Small clean-ups. Raymond Hettinger <python@rcn.com> parents: 64512 diff changeset	223 # has not been overridden or if a new getrandbits() was supplied.
64531 770c3ec05685 Minor refactoring and cleanup. Extend looping randrange() technique to subclasses. Raymond Hettinger <python@rcn.com> parents: 64523 diff changeset	224 if type(self.random) is BuiltinMethod or type(getrandbits) is Method:
64553 d5331712b509 In the case where only a user supplied random() method is available, Raymond Hettinger <python@rcn.com> parents: 64532 diff changeset	225 k = n.bit_length() # don't use (n-1) here because n can be 1
64532 89fe5179aec5 Neaten-up comments and warning message. Raymond Hettinger <python@rcn.com> parents: 64531 diff changeset	226 r = getrandbits(k) # 0 <= r < 2**k
64516 6ba20b9039ae Small clean-ups. Raymond Hettinger <python@rcn.com> parents: 64512 diff changeset	227 while r >= n:
30649 8841d34a2c37 SF bug #812202: randint is always even Raymond Hettinger <python@rcn.com> parents: 30346 diff changeset	228 r = getrandbits(k)
64516 6ba20b9039ae Small clean-ups. Raymond Hettinger <python@rcn.com> parents: 64512 diff changeset	229 return r
64531 770c3ec05685 Minor refactoring and cleanup. Extend looping randrange() technique to subclasses. Raymond Hettinger <python@rcn.com> parents: 64523 diff changeset	230 # There's an overriden random() method but no new getrandbits() method,
770c3ec05685 Minor refactoring and cleanup. Extend looping randrange() technique to subclasses. Raymond Hettinger <python@rcn.com> parents: 64523 diff changeset	231 # so we can only use random() from here.
64553 d5331712b509 In the case where only a user supplied random() method is available, Raymond Hettinger <python@rcn.com> parents: 64532 diff changeset	232 random = self.random
d5331712b509 In the case where only a user supplied random() method is available, Raymond Hettinger <python@rcn.com> parents: 64532 diff changeset	233 if n >= maxsize:
30649 8841d34a2c37 SF bug #812202: randint is always even Raymond Hettinger <python@rcn.com> parents: 30346 diff changeset	234 _warn("Underlying random() generator does not supply \n"
64532 89fe5179aec5 Neaten-up comments and warning message. Raymond Hettinger <python@rcn.com> parents: 64531 diff changeset	235 "enough bits to choose from a population range this large.\n"
89fe5179aec5 Neaten-up comments and warning message. Raymond Hettinger <python@rcn.com> parents: 64531 diff changeset	236 "To remove the range limitation, add a getrandbits() method.")
64553 d5331712b509 In the case where only a user supplied random() method is available, Raymond Hettinger <python@rcn.com> parents: 64532 diff changeset	237 return int(random() * n)
d5331712b509 In the case where only a user supplied random() method is available, Raymond Hettinger <python@rcn.com> parents: 64532 diff changeset	238 rem = maxsize % n
d5331712b509 In the case where only a user supplied random() method is available, Raymond Hettinger <python@rcn.com> parents: 64532 diff changeset	239 limit = (maxsize - rem) / maxsize # int(limit * maxsize) % n == 0
d5331712b509 In the case where only a user supplied random() method is available, Raymond Hettinger <python@rcn.com> parents: 64532 diff changeset	240 r = random()
d5331712b509 In the case where only a user supplied random() method is available, Raymond Hettinger <python@rcn.com> parents: 64532 diff changeset	241 while r >= limit:
d5331712b509 In the case where only a user supplied random() method is available, Raymond Hettinger <python@rcn.com> parents: 64532 diff changeset	242 r = random()
d5331712b509 In the case where only a user supplied random() method is available, Raymond Hettinger <python@rcn.com> parents: 64532 diff changeset	243 return int(r*maxsize) % n
30649 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."""
64517 e83af141dffd Fix corner case for Random.choice() and add tests. Raymond Hettinger <python@rcn.com> parents: 64516 diff changeset	249 try:
e83af141dffd Fix corner case for Random.choice() and add tests. Raymond Hettinger <python@rcn.com> parents: 64516 diff changeset	250 i = self._randbelow(len(seq))
e83af141dffd Fix corner case for Random.choice() and add tests. Raymond Hettinger <python@rcn.com> parents: 64516 diff changeset	251 except ValueError:
e83af141dffd Fix corner case for Random.choice() and add tests. Raymond Hettinger <python@rcn.com> parents: 64516 diff changeset	252 raise IndexError('Cannot choose from an empty sequence')
e83af141dffd Fix corner case for Random.choice() and add tests. Raymond Hettinger <python@rcn.com> parents: 64516 diff changeset	253 return seq[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	254
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 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	256 """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	257
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 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	259 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	260 """
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
64531 770c3ec05685 Minor refactoring and cleanup. Extend looping randrange() technique to subclasses. Raymond Hettinger <python@rcn.com> parents: 64523 diff changeset	262 randbelow = self._randbelow
41642 a6eb6acfe04a Merged revisions 55007-55179 via svnmerge from Guido van Rossum <guido@python.org> parents: 41592 diff changeset	263 for i in reversed(range(1, len(x))):
16265 d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	264 # pick an element in x[:i+1] with which to exchange x[i]
64531 770c3ec05685 Minor refactoring and cleanup. Extend looping randrange() technique to subclasses. Raymond Hettinger <python@rcn.com> parents: 64523 diff changeset	265 j = randbelow(i+1) if random is None else int(random() * (i+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	266 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	267
29430 b80a22250e4f SF bug #753602: random.sample not properly documented Raymond Hettinger <python@rcn.com> parents: 29250 diff changeset	268 def sample(self, population, k):
44665 91928d99ebb0 Take Tim's advice and have random.sample() support only sequences and sets. Raymond Hettinger <python@rcn.com> parents: 44662 diff changeset	269 """Chooses k unique random elements from a population sequence or set.
26155 8ceb455f5541 SF patch 629637: Add sample(population, k) method to the random module. Raymond Hettinger <python@rcn.com> parents: 24861 diff changeset	270
26178 83ae4a902df0 Improved clarity and thoroughness of docstring. Raymond Hettinger <python@rcn.com> parents: 26172 diff changeset	271 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	272 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	273 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	274 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	275 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	276
26178 83ae4a902df0 Improved clarity and thoroughness of docstring. Raymond Hettinger <python@rcn.com> parents: 26172 diff changeset	277 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	278 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	279 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	280
41642 a6eb6acfe04a Merged revisions 55007-55179 via svnmerge from Guido van Rossum <guido@python.org> parents: 41592 diff changeset	281 To choose a sample in a range of integers, use range as an argument.
26178 83ae4a902df0 Improved clarity and thoroughness of docstring. Raymond Hettinger <python@rcn.com> parents: 26172 diff changeset	282 This is especially fast and space efficient for sampling from a
41642 a6eb6acfe04a Merged revisions 55007-55179 via svnmerge from Guido van Rossum <guido@python.org> parents: 41592 diff changeset	283 large population: sample(range(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	284 """
8ceb455f5541 SF patch 629637: Add sample(population, k) method to the random module. Raymond Hettinger <python@rcn.com> parents: 24861 diff changeset	285
26178 83ae4a902df0 Improved clarity and thoroughness of docstring. Raymond Hettinger <python@rcn.com> parents: 26172 diff changeset	286 # 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	287 # 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	288
31578 8183dd1a4fe6 Reflow long line. Jeremy Hylton <jeremy@alum.mit.edu> parents: 31389 diff changeset	289 # When the number of selections is small compared to the
8183dd1a4fe6 Reflow long line. Jeremy Hylton <jeremy@alum.mit.edu> parents: 31389 diff changeset	290 # 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	291 # only a small set and an occasional reselection. For
31578 8183dd1a4fe6 Reflow long line. Jeremy Hylton <jeremy@alum.mit.edu> parents: 31389 diff changeset	292 # a larger number of selections, the pool tracking method is
8183dd1a4fe6 Reflow long line. Jeremy Hylton <jeremy@alum.mit.edu> parents: 31389 diff changeset	293 # 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	294 # 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	295
69859 e2f7db1255df Sync-up minor code edits with the default branch. Raymond Hettinger <python@rcn.com> parents: 69857 diff changeset	296 if isinstance(population, _Set):
44665 91928d99ebb0 Take Tim's advice and have random.sample() support only sequences and sets. Raymond Hettinger <python@rcn.com> parents: 44662 diff changeset	297 population = tuple(population)
69859 e2f7db1255df Sync-up minor code edits with the default branch. Raymond Hettinger <python@rcn.com> parents: 69857 diff changeset	298 if not isinstance(population, _Sequence):
e2f7db1255df Sync-up minor code edits with the default branch. Raymond Hettinger <python@rcn.com> parents: 69857 diff changeset	299 raise TypeError("Population must be a sequence or set. For dicts, use list(d).")
64531 770c3ec05685 Minor refactoring and cleanup. Extend looping randrange() technique to subclasses. Raymond Hettinger <python@rcn.com> parents: 64523 diff changeset	300 randbelow = self._randbelow
26155 8ceb455f5541 SF patch 629637: Add sample(population, k) method to the random module. Raymond Hettinger <python@rcn.com> parents: 24861 diff changeset	301 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	302 if not 0 <= k <= n:
44665 91928d99ebb0 Take Tim's advice and have random.sample() support only sequences and sets. Raymond Hettinger <python@rcn.com> parents: 44662 diff changeset	303 raise ValueError("Sample larger than population")
26178 83ae4a902df0 Improved clarity and thoroughness of docstring. Raymond Hettinger <python@rcn.com> parents: 26172 diff changeset	304 result = [None] * k
35359 c5bf5685267b Implement random.sample() using sets instead of dicts. Raymond Hettinger <python@rcn.com> parents: 34942 diff changeset	305 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	306 if k > 5:
35465 3e5c07faab11 Whitespace normalization (via reindent.py). Tim Peters <tim.peters@gmail.com> parents: 35359 diff changeset	307 setsize += 4 ** _ceil(_log(k * 3, 4)) # table size for big sets
44665 91928d99ebb0 Take Tim's advice and have random.sample() support only sequences and sets. Raymond Hettinger <python@rcn.com> parents: 44662 diff changeset	308 if n <= setsize:
91928d99ebb0 Take Tim's advice and have random.sample() support only sequences and sets. Raymond Hettinger <python@rcn.com> parents: 44662 diff changeset	309 # An n-length list is smaller than a k-length set
26266 42279f7d244d Improve comments. Clarify docs. Raymond Hettinger <python@rcn.com> parents: 26178 diff changeset	310 pool = list(population)
41642 a6eb6acfe04a Merged revisions 55007-55179 via svnmerge from Guido van Rossum <guido@python.org> parents: 41592 diff changeset	311 for i in range(k): # invariant: non-selected at [0,n-i)
64531 770c3ec05685 Minor refactoring and cleanup. Extend looping randrange() technique to subclasses. Raymond Hettinger <python@rcn.com> parents: 64523 diff changeset	312 j = randbelow(n-i)
26266 42279f7d244d Improve comments. Clarify docs. Raymond Hettinger <python@rcn.com> parents: 26178 diff changeset	313 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	314 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	315 else:
44665 91928d99ebb0 Take Tim's advice and have random.sample() support only sequences and sets. Raymond Hettinger <python@rcn.com> parents: 44662 diff changeset	316 selected = set()
91928d99ebb0 Take Tim's advice and have random.sample() support only sequences and sets. Raymond Hettinger <python@rcn.com> parents: 44662 diff changeset	317 selected_add = selected.add
91928d99ebb0 Take Tim's advice and have random.sample() support only sequences and sets. Raymond Hettinger <python@rcn.com> parents: 44662 diff changeset	318 for i in range(k):
64531 770c3ec05685 Minor refactoring and cleanup. Extend looping randrange() technique to subclasses. Raymond Hettinger <python@rcn.com> parents: 64523 diff changeset	319 j = randbelow(n)
44665 91928d99ebb0 Take Tim's advice and have random.sample() support only sequences and sets. Raymond Hettinger <python@rcn.com> parents: 44662 diff changeset	320 while j in selected:
64531 770c3ec05685 Minor refactoring and cleanup. Extend looping randrange() technique to subclasses. Raymond Hettinger <python@rcn.com> parents: 64523 diff changeset	321 j = randbelow(n)
44665 91928d99ebb0 Take Tim's advice and have random.sample() support only sequences and sets. Raymond Hettinger <python@rcn.com> parents: 44662 diff changeset	322 selected_add(j)
91928d99ebb0 Take Tim's advice and have random.sample() support only sequences and sets. Raymond Hettinger <python@rcn.com> parents: 44662 diff changeset	323 result[i] = population[j]
26266 42279f7d244d Improve comments. Clarify docs. Raymond Hettinger <python@rcn.com> parents: 26178 diff changeset	324 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	325
16265 d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	326 ## -------------------- real-valued distributions -------------------
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	327
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	328 ## -------------------- 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	329
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	330 def uniform(self, a, b):
54705 0e1b3c24d3e2 Issue 6261: Clarify behavior of random.uniform(). Raymond Hettinger <python@rcn.com> parents: 51834 diff changeset	331 "Get a random number in the range [a, b) or [a, b] depending on rounding."
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	332 return a + (b-a) * self.random()
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	333
46034 0a485593ae1c Merged revisions 61724-61725,61731-61735,61737,61739,61741,61743-61744,61753,61761,61765-61767,61769,61773,61776-61778,61780-61783,61788,61793,61796,61807,61813 via svnmerge from Christian Heimes <christian@cheimes.de> parents: 44665 diff changeset	334 ## -------------------- triangular --------------------
0a485593ae1c Merged revisions 61724-61725,61731-61735,61737,61739,61741,61743-61744,61753,61761,61765-61767,61769,61773,61776-61778,61780-61783,61788,61793,61796,61807,61813 via svnmerge from Christian Heimes <christian@cheimes.de> parents: 44665 diff changeset	335
0a485593ae1c Merged revisions 61724-61725,61731-61735,61737,61739,61741,61743-61744,61753,61761,61765-61767,61769,61773,61776-61778,61780-61783,61788,61793,61796,61807,61813 via svnmerge from Christian Heimes <christian@cheimes.de> parents: 44665 diff changeset	336 def triangular(self, low=0.0, high=1.0, mode=None):
0a485593ae1c Merged revisions 61724-61725,61731-61735,61737,61739,61741,61743-61744,61753,61761,61765-61767,61769,61773,61776-61778,61780-61783,61788,61793,61796,61807,61813 via svnmerge from Christian Heimes <christian@cheimes.de> parents: 44665 diff changeset	337 """Triangular distribution.
0a485593ae1c Merged revisions 61724-61725,61731-61735,61737,61739,61741,61743-61744,61753,61761,61765-61767,61769,61773,61776-61778,61780-61783,61788,61793,61796,61807,61813 via svnmerge from Christian Heimes <christian@cheimes.de> parents: 44665 diff changeset	338
0a485593ae1c Merged revisions 61724-61725,61731-61735,61737,61739,61741,61743-61744,61753,61761,61765-61767,61769,61773,61776-61778,61780-61783,61788,61793,61796,61807,61813 via svnmerge from Christian Heimes <christian@cheimes.de> parents: 44665 diff changeset	339 Continuous distribution bounded by given lower and upper limits,
0a485593ae1c Merged revisions 61724-61725,61731-61735,61737,61739,61741,61743-61744,61753,61761,61765-61767,61769,61773,61776-61778,61780-61783,61788,61793,61796,61807,61813 via svnmerge from Christian Heimes <christian@cheimes.de> parents: 44665 diff changeset	340 and having a given mode value in-between.
0a485593ae1c Merged revisions 61724-61725,61731-61735,61737,61739,61741,61743-61744,61753,61761,61765-61767,61769,61773,61776-61778,61780-61783,61788,61793,61796,61807,61813 via svnmerge from Christian Heimes <christian@cheimes.de> parents: 44665 diff changeset	341
0a485593ae1c Merged revisions 61724-61725,61731-61735,61737,61739,61741,61743-61744,61753,61761,61765-61767,61769,61773,61776-61778,61780-61783,61788,61793,61796,61807,61813 via svnmerge from Christian Heimes <christian@cheimes.de> parents: 44665 diff changeset	342 http://en.wikipedia.org/wiki/Triangular_distribution
0a485593ae1c Merged revisions 61724-61725,61731-61735,61737,61739,61741,61743-61744,61753,61761,61765-61767,61769,61773,61776-61778,61780-61783,61788,61793,61796,61807,61813 via svnmerge from Christian Heimes <christian@cheimes.de> parents: 44665 diff changeset	343
0a485593ae1c Merged revisions 61724-61725,61731-61735,61737,61739,61741,61743-61744,61753,61761,61765-61767,61769,61773,61776-61778,61780-61783,61788,61793,61796,61807,61813 via svnmerge from Christian Heimes <christian@cheimes.de> parents: 44665 diff changeset	344 """
0a485593ae1c Merged revisions 61724-61725,61731-61735,61737,61739,61741,61743-61744,61753,61761,61765-61767,61769,61773,61776-61778,61780-61783,61788,61793,61796,61807,61813 via svnmerge from Christian Heimes <christian@cheimes.de> parents: 44665 diff changeset	345 u = self.random()
0a485593ae1c Merged revisions 61724-61725,61731-61735,61737,61739,61741,61743-61744,61753,61761,61765-61767,61769,61773,61776-61778,61780-61783,61788,61793,61796,61807,61813 via svnmerge from Christian Heimes <christian@cheimes.de> parents: 44665 diff changeset	346 c = 0.5 if mode is None else (mode - low) / (high - low)
0a485593ae1c Merged revisions 61724-61725,61731-61735,61737,61739,61741,61743-61744,61753,61761,61765-61767,61769,61773,61776-61778,61780-61783,61788,61793,61796,61807,61813 via svnmerge from Christian Heimes <christian@cheimes.de> parents: 44665 diff changeset	347 if u > c:
0a485593ae1c Merged revisions 61724-61725,61731-61735,61737,61739,61741,61743-61744,61753,61761,61765-61767,61769,61773,61776-61778,61780-61783,61788,61793,61796,61807,61813 via svnmerge from Christian Heimes <christian@cheimes.de> parents: 44665 diff changeset	348 u = 1.0 - u
0a485593ae1c Merged revisions 61724-61725,61731-61735,61737,61739,61741,61743-61744,61753,61761,61765-61767,61769,61773,61776-61778,61780-61783,61788,61793,61796,61807,61813 via svnmerge from Christian Heimes <christian@cheimes.de> parents: 44665 diff changeset	349 c = 1.0 - c
0a485593ae1c Merged revisions 61724-61725,61731-61735,61737,61739,61741,61743-61744,61753,61761,61765-61767,61769,61773,61776-61778,61780-61783,61788,61793,61796,61807,61813 via svnmerge from Christian Heimes <christian@cheimes.de> parents: 44665 diff changeset	350 low, high = high, low
0a485593ae1c Merged revisions 61724-61725,61731-61735,61737,61739,61741,61743-61744,61753,61761,61765-61767,61769,61773,61776-61778,61780-61783,61788,61793,61796,61807,61813 via svnmerge from Christian Heimes <christian@cheimes.de> parents: 44665 diff changeset	351 return low + (high - low) * (u * c) ** 0.5
0a485593ae1c Merged revisions 61724-61725,61731-61735,61737,61739,61741,61743-61744,61753,61761,61765-61767,61769,61773,61776-61778,61780-61783,61788,61793,61796,61807,61813 via svnmerge from Christian Heimes <christian@cheimes.de> parents: 44665 diff changeset	352
16265 d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	353 ## -------------------- normal distribution --------------------
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	354
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 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	356 """Normal distribution.
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	357
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	358 mu is the mean, and sigma is the standard deviation.
23536 0a4c92559a0b Whitespace normalized. Raymond Hettinger <python@rcn.com> parents: 23531 diff changeset	359
23531 a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	360 """
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	361 # 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	362
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 # 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	364 # 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	365 # 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	366 # Math Software, 3, (1977), pp257-260.
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	367
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	368 random = self.random
34942 7287b41145ae SF patch #1191489: Simplify logic in random.py Raymond Hettinger <python@rcn.com> parents: 34312 diff changeset	369 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	370 u1 = random()
27085 90350b5d3397 Correct long standing bugs in the methods for random distributions. Raymond Hettinger <python@rcn.com> parents: 27080 diff changeset	371 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	372 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	373 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	374 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	375 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	376 return mu + z*sigma
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	377
16265 d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	378 ## -------------------- lognormal distribution --------------------
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	379
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	380 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	381 """Log normal distribution.
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	382
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	383 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	384 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	385 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	386
23531 a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	387 """
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 return _exp(self.normalvariate(mu, sigma))
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	389
16265 d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	390 ## -------------------- exponential distribution --------------------
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	391
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	392 def expovariate(self, lambd):
23531 a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	393 """Exponential distribution.
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	394
50626 fed2ae1e50c2 Merged revisions 68378 via svnmerge from Mark Dickinson <dickinsm@gmail.com> parents: 48596 diff changeset	395 lambd is 1.0 divided by the desired mean. It should be
fed2ae1e50c2 Merged revisions 68378 via svnmerge from Mark Dickinson <dickinsm@gmail.com> parents: 48596 diff changeset	396 nonzero. (The parameter would be called "lambda", but that is
fed2ae1e50c2 Merged revisions 68378 via svnmerge from Mark Dickinson <dickinsm@gmail.com> parents: 48596 diff changeset	397 a reserved word in Python.) Returned values range from 0 to
fed2ae1e50c2 Merged revisions 68378 via svnmerge from Mark Dickinson <dickinsm@gmail.com> parents: 48596 diff changeset	398 positive infinity if lambd is positive, and from negative
fed2ae1e50c2 Merged revisions 68378 via svnmerge from Mark Dickinson <dickinsm@gmail.com> parents: 48596 diff changeset	399 infinity to 0 if lambd is negative.
23536 0a4c92559a0b Whitespace normalized. Raymond Hettinger <python@rcn.com> parents: 23531 diff changeset	400
23531 a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	401 """
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	402 # 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	403 # ('lambda' is a Python reserved word)
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	404
70949 9216e0a5d950 Code simplification suggested by Sven Marnach. Raymond Hettinger <python@rcn.com> parents: 69859 diff changeset	405 # we use 1-random() instead of random() to preclude the
9216e0a5d950 Code simplification suggested by Sven Marnach. Raymond Hettinger <python@rcn.com> parents: 69859 diff changeset	406 # possibility of taking the log of zero.
9216e0a5d950 Code simplification suggested by Sven Marnach. Raymond Hettinger <python@rcn.com> parents: 69859 diff changeset	407 return -_log(1.0 - self.random())/lambd
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	408
16265 d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	409 ## -------------------- von Mises distribution --------------------
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: 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 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	412 """Circular data distribution.
23536 0a4c92559a0b Whitespace normalized. Raymond Hettinger <python@rcn.com> parents: 23531 diff changeset	413
23531 a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	414 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	415 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	416 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	417 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	418
23531 a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	419 """
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	420 # 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	421 # 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	422 # if kappa = 0 generate uniform random angle
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	423
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	424 # 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	425 # "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	426 # 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	427
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	428 # 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	429 # 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	430
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	431 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	432 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	433 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	434
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	435 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	436 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	437 r = (1.0 + b * b)/(2.0 * b)
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	438
34942 7287b41145ae SF patch #1191489: Simplify logic in random.py Raymond Hettinger <python@rcn.com> parents: 34312 diff changeset	439 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	440 u1 = random()
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	441
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	442 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	443 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	444 c = kappa * (r - f)
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	445
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	446 u2 = random()
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	447
34942 7287b41145ae SF patch #1191489: Simplify logic in random.py Raymond Hettinger <python@rcn.com> parents: 34312 diff changeset	448 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	449 break
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	450
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	451 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	452 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	453 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	454 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	455 theta = (mu % TWOPI) - _acos(f)
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	456
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	457 return theta
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	458
16265 d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	459 ## -------------------- gamma distribution --------------------
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 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	462 """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	463
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	464 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	465
68846 e880020e7e6a Issue 10787: Document the probability density function for random.gammavariate. Raymond Hettinger <python@rcn.com> parents: 57584 diff changeset	466 The probability distribution function is:
e880020e7e6a Issue 10787: Document the probability density function for random.gammavariate. Raymond Hettinger <python@rcn.com> parents: 57584 diff changeset	467
e880020e7e6a Issue 10787: Document the probability density function for random.gammavariate. Raymond Hettinger <python@rcn.com> parents: 57584 diff changeset	468 x ** (alpha - 1) * math.exp(-x / beta)
e880020e7e6a Issue 10787: Document the probability density function for random.gammavariate. Raymond Hettinger <python@rcn.com> parents: 57584 diff changeset	469 pdf(x) = --------------------------------------
e880020e7e6a Issue 10787: Document the probability density function for random.gammavariate. Raymond Hettinger <python@rcn.com> parents: 57584 diff changeset	470 math.gamma(alpha) * beta ** alpha
e880020e7e6a Issue 10787: Document the probability density function for random.gammavariate. Raymond Hettinger <python@rcn.com> parents: 57584 diff changeset	471
23531 a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	472 """
23521 a90faa5f9417 Whitespace normalization. Tim Peters <tim.peters@gmail.com> parents: 23451 diff changeset	473
23447 08ccb0f3e2d4 Closes patch 529408 deprecating random.stdgamma(). Raymond Hettinger <python@rcn.com> parents: 23442 diff changeset	474 # 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	475
23451 273dd2508c57 Use spaces, not tabs for indents. Guido van Rossum <guido@python.org> parents: 23447 diff changeset	476 # 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	477 # of alpha > -1.0
273dd2508c57 Use spaces, not tabs for indents. Guido van Rossum <guido@python.org> parents: 23447 diff changeset	478 if alpha <= 0.0 or beta <= 0.0:
43020 907a45df1295 Raise statement normalization in Lib/. Collin Winter <collinw@gmail.com> parents: 42084 diff changeset	479 raise ValueError('gammavariate: alpha and beta must be > 0.0')
23521 a90faa5f9417 Whitespace normalization. Tim Peters <tim.peters@gmail.com> parents: 23451 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 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	482 if alpha > 1.0:
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	483
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 # 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	485 # 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	486 # Applied Statistics, (1977), 26, No. 1, p71-74
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	487
23442 b15896053933 Closes SF bug 527139. Moved temp variables inside guard. Raymond Hettinger <python@rcn.com> parents: 23380 diff changeset	488 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	489 bbb = alpha - LOG4
b15896053933 Closes SF bug 527139. Moved temp variables inside guard. Raymond Hettinger <python@rcn.com> parents: 23380 diff changeset	490 ccc = alpha + ainv
23521 a90faa5f9417 Whitespace normalization. Tim Peters <tim.peters@gmail.com> parents: 23451 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 u1 = random()
27085 90350b5d3397 Correct long standing bugs in the methods for random distributions. Raymond Hettinger <python@rcn.com> parents: 27080 diff changeset	494 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	495 continue
90350b5d3397 Correct long standing bugs in the methods for random distributions. Raymond Hettinger <python@rcn.com> parents: 27080 diff changeset	496 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	497 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	498 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	499 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	500 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	501 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	502 return x * beta
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	503
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	504 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	505 # expovariate(1)
15871 62aeefa01fdd Whitespace normalization. Tim Peters <tim.peters@gmail.com> parents: 14617 diff changeset	506 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	507 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	508 u = random()
23447 08ccb0f3e2d4 Closes patch 529408 deprecating random.stdgamma(). Raymond Hettinger <python@rcn.com> parents: 23442 diff changeset	509 return -_log(u) * beta
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	510
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	511 else: # alpha is between 0 and 1 (exclusive)
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	512
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	513 # Uses ALGORITHM GS of Statistical Computing - Kennedy & Gentle
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	514
34942 7287b41145ae SF patch #1191489: Simplify logic in random.py Raymond Hettinger <python@rcn.com> parents: 34312 diff changeset	515 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	516 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	517 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	518 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	519 if p <= 1.0:
34942 7287b41145ae SF patch #1191489: Simplify logic in random.py Raymond Hettinger <python@rcn.com> parents: 34312 diff changeset	520 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	521 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	522 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	523 u1 = random()
34942 7287b41145ae SF patch #1191489: Simplify logic in random.py Raymond Hettinger <python@rcn.com> parents: 34312 diff changeset	524 if p > 1.0:
7287b41145ae SF patch #1191489: Simplify logic in random.py Raymond Hettinger <python@rcn.com> parents: 34312 diff changeset	525 if u1 <= x ** (alpha - 1.0):
7287b41145ae SF patch #1191489: Simplify logic in random.py Raymond Hettinger <python@rcn.com> parents: 34312 diff changeset	526 break
7287b41145ae SF patch #1191489: Simplify logic in random.py Raymond Hettinger <python@rcn.com> parents: 34312 diff changeset	527 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	528 break
23447 08ccb0f3e2d4 Closes patch 529408 deprecating random.stdgamma(). Raymond Hettinger <python@rcn.com> parents: 23442 diff changeset	529 return x * beta
08ccb0f3e2d4 Closes patch 529408 deprecating random.stdgamma(). Raymond Hettinger <python@rcn.com> parents: 23442 diff changeset	530
16265 d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	531 ## -------------------- 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	532
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	533 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	534 """Gaussian distribution.
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	535
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	536 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	537 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	538
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	539 Not thread-safe without a lock around calls.
23536 0a4c92559a0b Whitespace normalized. Raymond Hettinger <python@rcn.com> parents: 23531 diff changeset	540
23531 a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	541 """
1577 444e349f962f Use float constants directly; cosmetic changes; initialize largest Guido van Rossum <guido@python.org> parents: 1576 diff changeset	542
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	543 # 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	544 # 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	545 #
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	546 # 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	547 # 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	548 #
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	549 # 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	550 # (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	551 # (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	552 # (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	553
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	554 # 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	555 # 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	556 # 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	557 # 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	558 # 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	559 # lock here.)
1577 444e349f962f Use float constants directly; cosmetic changes; initialize largest Guido van Rossum <guido@python.org> parents: 1576 diff changeset	560
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	561 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	562 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	563 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	564 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	565 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	566 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	567 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	568 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	569
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	570 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	571
16265 d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	572 ## -------------------- beta --------------------
16271 7ef2382f6123 SF bug 130030: Claim of bad betavariate algorithm. Tim Peters <tim.peters@gmail.com> parents: 16265 diff changeset	573 ## See
69362 f5b9ad73157c #11848: replace dead link in random.betavariate comment. Ezio Melotti <ezio.melotti@gmail.com> parents: 68846 diff changeset	574 ## http://mail.python.org/pipermail/python-bugs-list/2001-January/003752.html
16271 7ef2382f6123 SF bug 130030: Claim of bad betavariate algorithm. Tim Peters <tim.peters@gmail.com> parents: 16265 diff changeset	575 ## 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	576 ##
7ef2382f6123 SF bug 130030: Claim of bad betavariate algorithm. Tim Peters <tim.peters@gmail.com> parents: 16265 diff changeset	577 ## def betavariate(self, alpha, beta):
7ef2382f6123 SF bug 130030: Claim of bad betavariate algorithm. Tim Peters <tim.peters@gmail.com> parents: 16265 diff changeset	578 ## # 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	579 ##
7ef2382f6123 SF bug 130030: Claim of bad betavariate algorithm. Tim Peters <tim.peters@gmail.com> parents: 16265 diff changeset	580 ## y = self.expovariate(alpha)
7ef2382f6123 SF bug 130030: Claim of bad betavariate algorithm. Tim Peters <tim.peters@gmail.com> parents: 16265 diff changeset	581 ## 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	582 ## return z/(y+z)
7ef2382f6123 SF bug 130030: Claim of bad betavariate algorithm. Tim Peters <tim.peters@gmail.com> parents: 16265 diff changeset	583 ##
7ef2382f6123 SF bug 130030: Claim of bad betavariate algorithm. Tim Peters <tim.peters@gmail.com> parents: 16265 diff changeset	584 ## 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	585
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 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	587 """Beta distribution.
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	588
40737 6ebad2a6b990 Merged revisions 53451-53537 via svnmerge from Thomas Wouters <thomas@python.org> parents: 40644 diff changeset	589 Conditions on the parameters are alpha > 0 and beta > 0.
23531 a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	590 Returned values range between 0 and 1.
23536 0a4c92559a0b Whitespace normalized. Raymond Hettinger <python@rcn.com> parents: 23531 diff changeset	591
23531 a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	592 """
23536 0a4c92559a0b Whitespace normalized. Raymond Hettinger <python@rcn.com> parents: 23531 diff changeset	593
16271 7ef2382f6123 SF bug 130030: Claim of bad betavariate algorithm. Tim Peters <tim.peters@gmail.com> parents: 16265 diff changeset	594 # 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	595 # 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	596 y = self.gammavariate(alpha, 1.)
7ef2382f6123 SF bug 130030: Claim of bad betavariate algorithm. Tim Peters <tim.peters@gmail.com> parents: 16265 diff changeset	597 if y == 0:
7ef2382f6123 SF bug 130030: Claim of bad betavariate algorithm. Tim Peters <tim.peters@gmail.com> parents: 16265 diff changeset	598 return 0.0
7ef2382f6123 SF bug 130030: Claim of bad betavariate algorithm. Tim Peters <tim.peters@gmail.com> parents: 16265 diff changeset	599 else:
7ef2382f6123 SF bug 130030: Claim of bad betavariate algorithm. Tim Peters <tim.peters@gmail.com> parents: 16265 diff changeset	600 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	601
16265 d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	602 ## -------------------- Pareto --------------------
6698 b73eb4e6face Added Pareto and Weibull distributions, courtesy Jeremy Hylton. Guido van Rossum <guido@python.org> parents: 1618 diff changeset	603
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	604 def paretovariate(self, alpha):
23531 a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	605 """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	606 # Jain, pg. 495
6698 b73eb4e6face Added Pareto and Weibull distributions, courtesy Jeremy Hylton. Guido van Rossum <guido@python.org> parents: 1618 diff changeset	607
27085 90350b5d3397 Correct long standing bugs in the methods for random distributions. Raymond Hettinger <python@rcn.com> parents: 27080 diff changeset	608 u = 1.0 - self.random()
64568 7c2eb5b6cc58 One more conversion from pow() to *. Raymond Hettinger <python@rcn.com>* parents: 64567 diff changeset	609 return 1.0 / u ** (1.0/alpha)
6698 b73eb4e6face Added Pareto and Weibull distributions, courtesy Jeremy Hylton. Guido van Rossum <guido@python.org> parents: 1618 diff changeset	610
16265 d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	611 ## -------------------- Weibull --------------------
6698 b73eb4e6face Added Pareto and Weibull distributions, courtesy Jeremy Hylton. Guido van Rossum <guido@python.org> parents: 1618 diff changeset	612
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	613 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	614 """Weibull distribution.
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	615
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	616 alpha is the scale parameter and beta is the shape parameter.
23536 0a4c92559a0b Whitespace normalized. Raymond Hettinger <python@rcn.com> parents: 23531 diff changeset	617
23531 a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	618 """
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	619 # 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	620
27085 90350b5d3397 Correct long standing bugs in the methods for random distributions. Raymond Hettinger <python@rcn.com> parents: 27080 diff changeset	621 u = 1.0 - self.random()
64567 b1865ca7b65c * Remove dependency on binascii.hexlify by using int.from_bytes(). Raymond Hettinger <python@rcn.com> parents: 64553 diff changeset	622 return alpha * (-_log(u)) ** (1.0/beta)
11200 bca2d14f3e36 Add Tim Peters' shuffle() algorithm. Guido van Rossum <guido@python.org> parents: 8802 diff changeset	623
33481 eacdc29606d8 SF #1027105: HardwareRandom should be renamed OSRandom Raymond Hettinger <python@rcn.com> parents: 33409 diff changeset	624 ## --------------- Operating System Random Source ------------------
33329 97fca735c8da Teach the random module about os.urandom(). Raymond Hettinger <python@rcn.com> parents: 32287 diff changeset	625
33481 eacdc29606d8 SF #1027105: HardwareRandom should be renamed OSRandom Raymond Hettinger <python@rcn.com> parents: 33409 diff changeset	626 class SystemRandom(Random):
eacdc29606d8 SF #1027105: HardwareRandom should be renamed OSRandom Raymond Hettinger <python@rcn.com> parents: 33409 diff changeset	627 """Alternate random number generator using sources provided
eacdc29606d8 SF #1027105: HardwareRandom should be renamed OSRandom Raymond Hettinger <python@rcn.com> parents: 33409 diff changeset	628 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	629 CryptGenRandom on Windows).
33329 97fca735c8da Teach the random module about os.urandom(). Raymond Hettinger <python@rcn.com> parents: 32287 diff changeset	630
97fca735c8da Teach the random module about os.urandom(). Raymond Hettinger <python@rcn.com> parents: 32287 diff changeset	631 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	632 """
97fca735c8da Teach the random module about os.urandom(). Raymond Hettinger <python@rcn.com> parents: 32287 diff changeset	633
97fca735c8da Teach the random module about os.urandom(). Raymond Hettinger <python@rcn.com> parents: 32287 diff changeset	634 def random(self):
97fca735c8da Teach the random module about os.urandom(). Raymond Hettinger <python@rcn.com> parents: 32287 diff changeset	635 """Get the next random number in the range [0.0, 1.0)."""
64567 b1865ca7b65c * Remove dependency on binascii.hexlify by using int.from_bytes(). Raymond Hettinger <python@rcn.com> parents: 64553 diff changeset	636 return (int.from_bytes(_urandom(7), 'big') >> 3) * RECIP_BPF
33329 97fca735c8da Teach the random module about os.urandom(). Raymond Hettinger <python@rcn.com> parents: 32287 diff changeset	637
97fca735c8da Teach the random module about os.urandom(). Raymond Hettinger <python@rcn.com> parents: 32287 diff changeset	638 def getrandbits(self, k):
97fca735c8da Teach the random module about os.urandom(). Raymond Hettinger <python@rcn.com> parents: 32287 diff changeset	639 """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	640 if k <= 0:
97fca735c8da Teach the random module about os.urandom(). Raymond Hettinger <python@rcn.com> parents: 32287 diff changeset	641 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	642 if k != int(k):
97fca735c8da Teach the random module about os.urandom(). Raymond Hettinger <python@rcn.com> parents: 32287 diff changeset	643 raise TypeError('number of bits should be an integer')
64569 8627c3ec9711 Improve variable name (don't shadow a builtin). Raymond Hettinger <python@rcn.com> parents: 64568 diff changeset	644 numbytes = (k + 7) // 8 # bits / 8 and rounded up
8627c3ec9711 Improve variable name (don't shadow a builtin). Raymond Hettinger <python@rcn.com> parents: 64568 diff changeset	645 x = int.from_bytes(_urandom(numbytes), 'big')
8627c3ec9711 Improve variable name (don't shadow a builtin). Raymond Hettinger <python@rcn.com> parents: 64568 diff changeset	646 return x >> (numbytes * 8 - k) # trim excess bits
33329 97fca735c8da Teach the random module about os.urandom(). Raymond Hettinger <python@rcn.com> parents: 32287 diff changeset	647
44662 c25760c21397 Remove defunct parts of the random module Raymond Hettinger <python@rcn.com> parents: 44129 diff changeset	648 def seed(self, args, *kwds):
33481 eacdc29606d8 SF #1027105: HardwareRandom should be renamed OSRandom Raymond Hettinger <python@rcn.com> parents: 33409 diff changeset	649 "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	650 return None
97fca735c8da Teach the random module about os.urandom(). Raymond Hettinger <python@rcn.com> parents: 32287 diff changeset	651
97fca735c8da Teach the random module about os.urandom(). Raymond Hettinger <python@rcn.com> parents: 32287 diff changeset	652 def _notimplemented(self, args, *kwds):
33481 eacdc29606d8 SF #1027105: HardwareRandom should be renamed OSRandom Raymond Hettinger <python@rcn.com> parents: 33409 diff changeset	653 "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	654 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	655 getstate = setstate = _notimplemented
97fca735c8da Teach the random module about os.urandom(). Raymond Hettinger <python@rcn.com> parents: 32287 diff changeset	656
16265 d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	657 ## -------------------- test program --------------------
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	658
30243 53a322c6de52 Eliminate unnecessary eval() in tests Raymond Hettinger <python@rcn.com> parents: 30114 diff changeset	659 def _test_generator(n, func, args):
15871 62aeefa01fdd Whitespace normalization. Tim Peters <tim.peters@gmail.com> parents: 14617 diff changeset	660 import time
40775 4cdf21a0dbbc Fix most trivially-findable print statements. Guido van Rossum <guido@python.org> parents: 40737 diff changeset	661 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	662 total = 0.0
15871 62aeefa01fdd Whitespace normalization. Tim Peters <tim.peters@gmail.com> parents: 14617 diff changeset	663 sqsum = 0.0
62aeefa01fdd Whitespace normalization. Tim Peters <tim.peters@gmail.com> parents: 14617 diff changeset	664 smallest = 1e10
62aeefa01fdd Whitespace normalization. Tim Peters <tim.peters@gmail.com> parents: 14617 diff changeset	665 largest = -1e10
62aeefa01fdd Whitespace normalization. Tim Peters <tim.peters@gmail.com> parents: 14617 diff changeset	666 t0 = time.time()
62aeefa01fdd Whitespace normalization. Tim Peters <tim.peters@gmail.com> parents: 14617 diff changeset	667 for i in range(n):
30243 53a322c6de52 Eliminate unnecessary eval() in tests Raymond Hettinger <python@rcn.com> parents: 30114 diff changeset	668 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	669 total += x
15871 62aeefa01fdd Whitespace normalization. Tim Peters <tim.peters@gmail.com> parents: 14617 diff changeset	670 sqsum = sqsum + x*x
62aeefa01fdd Whitespace normalization. Tim Peters <tim.peters@gmail.com> parents: 14617 diff changeset	671 smallest = min(x, smallest)
62aeefa01fdd Whitespace normalization. Tim Peters <tim.peters@gmail.com> parents: 14617 diff changeset	672 largest = max(x, largest)
62aeefa01fdd Whitespace normalization. Tim Peters <tim.peters@gmail.com> parents: 14617 diff changeset	673 t1 = time.time()
40775 4cdf21a0dbbc Fix most trivially-findable print statements. Guido van Rossum <guido@python.org> parents: 40737 diff changeset	674 print(round(t1-t0, 3), 'sec,', end=' ')
29250 34609fa35b11 'sum' is no longer a good variable name. Use 'total' instead. Raymond Hettinger <python@rcn.com> parents: 27279 diff changeset	675 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	676 stddev = _sqrt(sqsum/n - avg*avg)
40775 4cdf21a0dbbc Fix most trivially-findable print statements. Guido van Rossum <guido@python.org> parents: 40737 diff changeset	677 print('avg %g, stddev %g, min %g, max %g' % \
4cdf21a0dbbc Fix most trivially-findable print statements. Guido van Rossum <guido@python.org> parents: 40737 diff changeset	678 (avg, stddev, smallest, largest))
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	679
26155 8ceb455f5541 SF patch 629637: Add sample(population, k) method to the random module. Raymond Hettinger <python@rcn.com> parents: 24861 diff changeset	680
8ceb455f5541 SF patch 629637: Add sample(population, k) method to the random module. Raymond Hettinger <python@rcn.com> parents: 24861 diff changeset	681 def _test(N=2000):
30243 53a322c6de52 Eliminate unnecessary eval() in tests Raymond Hettinger <python@rcn.com> parents: 30114 diff changeset	682 _test_generator(N, random, ())
53a322c6de52 Eliminate unnecessary eval() in tests Raymond Hettinger <python@rcn.com> parents: 30114 diff changeset	683 _test_generator(N, normalvariate, (0.0, 1.0))
53a322c6de52 Eliminate unnecessary eval() in tests Raymond Hettinger <python@rcn.com> parents: 30114 diff changeset	684 _test_generator(N, lognormvariate, (0.0, 1.0))
53a322c6de52 Eliminate unnecessary eval() in tests Raymond Hettinger <python@rcn.com> parents: 30114 diff changeset	685 _test_generator(N, vonmisesvariate, (0.0, 1.0))
53a322c6de52 Eliminate unnecessary eval() in tests Raymond Hettinger <python@rcn.com> parents: 30114 diff changeset	686 _test_generator(N, gammavariate, (0.01, 1.0))
53a322c6de52 Eliminate unnecessary eval() in tests Raymond Hettinger <python@rcn.com> parents: 30114 diff changeset	687 _test_generator(N, gammavariate, (0.1, 1.0))
53a322c6de52 Eliminate unnecessary eval() in tests Raymond Hettinger <python@rcn.com> parents: 30114 diff changeset	688 _test_generator(N, gammavariate, (0.1, 2.0))
53a322c6de52 Eliminate unnecessary eval() in tests Raymond Hettinger <python@rcn.com> parents: 30114 diff changeset	689 _test_generator(N, gammavariate, (0.5, 1.0))
53a322c6de52 Eliminate unnecessary eval() in tests Raymond Hettinger <python@rcn.com> parents: 30114 diff changeset	690 _test_generator(N, gammavariate, (0.9, 1.0))
53a322c6de52 Eliminate unnecessary eval() in tests Raymond Hettinger <python@rcn.com> parents: 30114 diff changeset	691 _test_generator(N, gammavariate, (1.0, 1.0))
53a322c6de52 Eliminate unnecessary eval() in tests Raymond Hettinger <python@rcn.com> parents: 30114 diff changeset	692 _test_generator(N, gammavariate, (2.0, 1.0))
53a322c6de52 Eliminate unnecessary eval() in tests Raymond Hettinger <python@rcn.com> parents: 30114 diff changeset	693 _test_generator(N, gammavariate, (20.0, 1.0))
53a322c6de52 Eliminate unnecessary eval() in tests Raymond Hettinger <python@rcn.com> parents: 30114 diff changeset	694 _test_generator(N, gammavariate, (200.0, 1.0))
53a322c6de52 Eliminate unnecessary eval() in tests Raymond Hettinger <python@rcn.com> parents: 30114 diff changeset	695 _test_generator(N, gauss, (0.0, 1.0))
53a322c6de52 Eliminate unnecessary eval() in tests Raymond Hettinger <python@rcn.com> parents: 30114 diff changeset	696 _test_generator(N, betavariate, (3.0, 3.0))
46034 0a485593ae1c Merged revisions 61724-61725,61731-61735,61737,61739,61741,61743-61744,61753,61761,61765-61767,61769,61773,61776-61778,61780-61783,61788,61793,61796,61807,61813 via svnmerge from Christian Heimes <christian@cheimes.de> parents: 44665 diff changeset	697 _test_generator(N, triangular, (0.0, 1.0, 1.0/3.0))
16265 d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	698
16292 0501c2a10315 New comment block to Clarify a subtlety. Tim Peters <tim.peters@gmail.com> parents: 16272 diff changeset	699 # 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	700 # 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	701 #(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	702 # 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	703 # 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	704
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	705 _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	706 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	707 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	708 uniform = _inst.uniform
46034 0a485593ae1c Merged revisions 61724-61725,61731-61735,61737,61739,61741,61743-61744,61753,61761,61765-61767,61769,61773,61776-61778,61780-61783,61788,61793,61796,61807,61813 via svnmerge from Christian Heimes <christian@cheimes.de> parents: 44665 diff changeset	709 triangular = _inst.triangular
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	710 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	711 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	712 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	713 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	714 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	715 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	716 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	717 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	718 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	719 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	720 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	721 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	722 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	723 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	724 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	725 setstate = _inst.setstate
30649 8841d34a2c37 SF bug #812202: randint is always even Raymond Hettinger <python@rcn.com> parents: 30346 diff changeset	726 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	727
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	728 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	729 _test()

Mercurial > cpython-lru_cache-weakref

annotate Lib/random.py @ 71285:8bc9dbc61ba6 3.2