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

annotate Lib/random.py @ 22360:c8a6ea00a9e1 legacy-trunk

restructure a bit to not rely on test case execution ordering add test case for bug #482460

author	Skip Montanaro <skip@pobox.com>
date	Sun, 17 Mar 2002 23:03:42 +0000
parents	fed5071da957
children	899002a882a0

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
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	10 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	11
11707 6f4146846337 The third and final doc-string sweep by Ka-Ping Yee. Guido van Rossum <guido@python.org> parents: 11200 diff changeset	12 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	13 ------------------------------
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	14 uniform
11707 6f4146846337 The third and final doc-string sweep by Ka-Ping Yee. Guido van Rossum <guido@python.org> parents: 11200 diff changeset	15 normal (Gaussian)
6f4146846337 The third and final doc-string sweep by Ka-Ping Yee. Guido van Rossum <guido@python.org> parents: 11200 diff changeset	16 lognormal
6f4146846337 The third and final doc-string sweep by Ka-Ping Yee. Guido van Rossum <guido@python.org> parents: 11200 diff changeset	17 negative exponential
6f4146846337 The third and final doc-string sweep by Ka-Ping Yee. Guido van Rossum <guido@python.org> parents: 11200 diff changeset	18 gamma
6f4146846337 The third and final doc-string sweep by Ka-Ping Yee. Guido van Rossum <guido@python.org> parents: 11200 diff changeset	19 beta
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	20
11707 6f4146846337 The third and final doc-string sweep by Ka-Ping Yee. Guido van Rossum <guido@python.org> parents: 11200 diff changeset	21 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	22 ---------------------------------------------
6f4146846337 The third and final doc-string sweep by Ka-Ping Yee. Guido van Rossum <guido@python.org> parents: 11200 diff changeset	23 circular uniform
6f4146846337 The third and final doc-string sweep by Ka-Ping Yee. Guido van Rossum <guido@python.org> parents: 11200 diff changeset	24 von Mises
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	25
11707 6f4146846337 The third and final doc-string sweep by Ka-Ping Yee. Guido van Rossum <guido@python.org> parents: 11200 diff changeset	26 Translated from anonymously contributed C/C++ source.
6f4146846337 The third and final doc-string sweep by Ka-Ping Yee. Guido van Rossum <guido@python.org> parents: 11200 diff changeset	27
16272 835e9dd54bfb The combo of getstate/setstate/jumpahead is very powerful, but needs Tim Peters <tim.peters@gmail.com> parents: 16271 diff changeset	28 Multi-threading note: the random number generator used here is not thread-
835e9dd54bfb The combo of getstate/setstate/jumpahead is very powerful, but needs Tim Peters <tim.peters@gmail.com> parents: 16271 diff changeset	29 safe; it is possible that two calls return the same random value. However,
835e9dd54bfb The combo of getstate/setstate/jumpahead is very powerful, but needs Tim Peters <tim.peters@gmail.com> parents: 16271 diff changeset	30 you can instantiate a different instance of Random() in each thread to get
835e9dd54bfb The combo of getstate/setstate/jumpahead is very powerful, but needs Tim Peters <tim.peters@gmail.com> parents: 16271 diff changeset	31 generators that don't share state, then use .setstate() and .jumpahead() to
835e9dd54bfb The combo of getstate/setstate/jumpahead is very powerful, but needs Tim Peters <tim.peters@gmail.com> parents: 16271 diff changeset	32 move the generators to disjoint segments of the full period. For example,
835e9dd54bfb The combo of getstate/setstate/jumpahead is very powerful, but needs Tim Peters <tim.peters@gmail.com> parents: 16271 diff changeset	33
835e9dd54bfb The combo of getstate/setstate/jumpahead is very powerful, but needs Tim Peters <tim.peters@gmail.com> parents: 16271 diff changeset	34 def create_generators(num, delta, firstseed=None):
835e9dd54bfb The combo of getstate/setstate/jumpahead is very powerful, but needs Tim Peters <tim.peters@gmail.com> parents: 16271 diff changeset	35 ""\"Return list of num distinct generators.
835e9dd54bfb The combo of getstate/setstate/jumpahead is very powerful, but needs Tim Peters <tim.peters@gmail.com> parents: 16271 diff changeset	36 Each generator has its own unique segment of delta elements from
835e9dd54bfb The combo of getstate/setstate/jumpahead is very powerful, but needs Tim Peters <tim.peters@gmail.com> parents: 16271 diff changeset	37 Random.random()'s full period.
835e9dd54bfb The combo of getstate/setstate/jumpahead is very powerful, but needs Tim Peters <tim.peters@gmail.com> parents: 16271 diff changeset	38 Seed the first generator with optional arg firstseed (default is
835e9dd54bfb The combo of getstate/setstate/jumpahead is very powerful, but needs Tim Peters <tim.peters@gmail.com> parents: 16271 diff changeset	39 None, to seed from current time).
835e9dd54bfb The combo of getstate/setstate/jumpahead is very powerful, but needs Tim Peters <tim.peters@gmail.com> parents: 16271 diff changeset	40 ""\"
835e9dd54bfb The combo of getstate/setstate/jumpahead is very powerful, but needs Tim Peters <tim.peters@gmail.com> parents: 16271 diff changeset	41
835e9dd54bfb The combo of getstate/setstate/jumpahead is very powerful, but needs Tim Peters <tim.peters@gmail.com> parents: 16271 diff changeset	42 from random import Random
835e9dd54bfb The combo of getstate/setstate/jumpahead is very powerful, but needs Tim Peters <tim.peters@gmail.com> parents: 16271 diff changeset	43 g = Random(firstseed)
835e9dd54bfb The combo of getstate/setstate/jumpahead is very powerful, but needs Tim Peters <tim.peters@gmail.com> parents: 16271 diff changeset	44 result = [g]
835e9dd54bfb The combo of getstate/setstate/jumpahead is very powerful, but needs Tim Peters <tim.peters@gmail.com> parents: 16271 diff changeset	45 for i in range(num - 1):
835e9dd54bfb The combo of getstate/setstate/jumpahead is very powerful, but needs Tim Peters <tim.peters@gmail.com> parents: 16271 diff changeset	46 laststate = g.getstate()
835e9dd54bfb The combo of getstate/setstate/jumpahead is very powerful, but needs Tim Peters <tim.peters@gmail.com> parents: 16271 diff changeset	47 g = Random()
835e9dd54bfb The combo of getstate/setstate/jumpahead is very powerful, but needs Tim Peters <tim.peters@gmail.com> parents: 16271 diff changeset	48 g.setstate(laststate)
835e9dd54bfb The combo of getstate/setstate/jumpahead is very powerful, but needs Tim Peters <tim.peters@gmail.com> parents: 16271 diff changeset	49 g.jumpahead(delta)
835e9dd54bfb The combo of getstate/setstate/jumpahead is very powerful, but needs Tim Peters <tim.peters@gmail.com> parents: 16271 diff changeset	50 result.append(g)
835e9dd54bfb The combo of getstate/setstate/jumpahead is very powerful, but needs Tim Peters <tim.peters@gmail.com> parents: 16271 diff changeset	51 return result
835e9dd54bfb The combo of getstate/setstate/jumpahead is very powerful, but needs Tim Peters <tim.peters@gmail.com> parents: 16271 diff changeset	52
835e9dd54bfb The combo of getstate/setstate/jumpahead is very powerful, but needs Tim Peters <tim.peters@gmail.com> parents: 16271 diff changeset	53 gens = create_generators(10, 1000000)
835e9dd54bfb The combo of getstate/setstate/jumpahead is very powerful, but needs Tim Peters <tim.peters@gmail.com> parents: 16271 diff changeset	54
835e9dd54bfb The combo of getstate/setstate/jumpahead is very powerful, but needs Tim Peters <tim.peters@gmail.com> parents: 16271 diff changeset	55 That creates 10 distinct generators, which can be passed out to 10 distinct
835e9dd54bfb The combo of getstate/setstate/jumpahead is very powerful, but needs Tim Peters <tim.peters@gmail.com> parents: 16271 diff changeset	56 threads. The generators don't share state so can be called safely in
835e9dd54bfb The combo of getstate/setstate/jumpahead is very powerful, but needs Tim Peters <tim.peters@gmail.com> parents: 16271 diff changeset	57 parallel. So long as no thread calls its g.random() more than a million
835e9dd54bfb The combo of getstate/setstate/jumpahead is very powerful, but needs Tim Peters <tim.peters@gmail.com> parents: 16271 diff changeset	58 times (the second argument to create_generators), the sequences seen by
835e9dd54bfb The combo of getstate/setstate/jumpahead is very powerful, but needs Tim Peters <tim.peters@gmail.com> parents: 16271 diff changeset	59 each thread will not overlap.
835e9dd54bfb The combo of getstate/setstate/jumpahead is very powerful, but needs Tim Peters <tim.peters@gmail.com> parents: 16271 diff changeset	60
835e9dd54bfb The combo of getstate/setstate/jumpahead is very powerful, but needs Tim Peters <tim.peters@gmail.com> parents: 16271 diff changeset	61 The period of the underlying Wichmann-Hill generator is 6,953,607,871,644,
835e9dd54bfb The combo of getstate/setstate/jumpahead is very powerful, but needs Tim Peters <tim.peters@gmail.com> parents: 16271 diff changeset	62 and that limits how far this technique can be pushed.
835e9dd54bfb The combo of getstate/setstate/jumpahead is very powerful, but needs Tim Peters <tim.peters@gmail.com> parents: 16271 diff changeset	63
835e9dd54bfb The combo of getstate/setstate/jumpahead is very powerful, but needs Tim Peters <tim.peters@gmail.com> parents: 16271 diff changeset	64 Just for fun, note that since we know the period, .jumpahead() can also be
835e9dd54bfb The combo of getstate/setstate/jumpahead is very powerful, but needs Tim Peters <tim.peters@gmail.com> parents: 16271 diff changeset	65 used to "move backward in time":
835e9dd54bfb The combo of getstate/setstate/jumpahead is very powerful, but needs Tim Peters <tim.peters@gmail.com> parents: 16271 diff changeset	66
835e9dd54bfb The combo of getstate/setstate/jumpahead is very powerful, but needs Tim Peters <tim.peters@gmail.com> parents: 16271 diff changeset	67 >>> g = Random(42) # arbitrary
835e9dd54bfb The combo of getstate/setstate/jumpahead is very powerful, but needs Tim Peters <tim.peters@gmail.com> parents: 16271 diff changeset	68 >>> g.random()
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	69 0.25420336316883324
16272 835e9dd54bfb The combo of getstate/setstate/jumpahead is very powerful, but needs Tim Peters <tim.peters@gmail.com> parents: 16271 diff changeset	70 >>> g.jumpahead(6953607871644L - 1) # move back one
835e9dd54bfb The combo of getstate/setstate/jumpahead is very powerful, but needs Tim Peters <tim.peters@gmail.com> parents: 16271 diff changeset	71 >>> g.random()
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	72 0.25420336316883324
11707 6f4146846337 The third and final doc-string sweep by Ka-Ping Yee. Guido van Rossum <guido@python.org> parents: 11200 diff changeset	73 """
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	74 # XXX The docstring sucks.
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	75
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	76 from math import log as _log, exp as _exp, pi as _pi, e as _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	77 from math import sqrt as _sqrt, acos as _acos, cos as _cos, sin as _sin
8455 af9273b1073a Make gauss() semi-thread-safe. It can still give duplicate results, Guido van Rossum <guido@python.org> parents: 8393 diff changeset	78
16613 f68dbffff927 bunch more __all__ lists Skip Montanaro <skip@pobox.com> parents: 16386 diff changeset	79 __all__ = ["Random","seed","random","uniform","randint","choice",
f68dbffff927 bunch more __all__ lists Skip Montanaro <skip@pobox.com> parents: 16386 diff changeset	80 "randrange","shuffle","normalvariate","lognormvariate",
f68dbffff927 bunch more __all__ lists Skip Montanaro <skip@pobox.com> parents: 16386 diff changeset	81 "cunifvariate","expovariate","vonmisesvariate","gammavariate",
f68dbffff927 bunch more __all__ lists Skip Montanaro <skip@pobox.com> parents: 16386 diff changeset	82 "stdgamma","gauss","betavariate","paretovariate","weibullvariate",
f68dbffff927 bunch more __all__ lists Skip Montanaro <skip@pobox.com> parents: 16386 diff changeset	83 "getstate","setstate","jumpahead","whseed"]
16616 e2a63584566f Whitespace normalization. Tim Peters <tim.peters@gmail.com> parents: 16613 diff changeset	84
21049 fed5071da957 SF patch 483059: Avoid use of eval() in random.py, from Finn Bock. Tim Peters <tim.peters@gmail.com> parents: 16616 diff changeset	85 def _verify(name, computed, expected):
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	86 if abs(computed - expected) > 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	87 raise ValueError(
3c5f09422b69 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 "computed value for %s deviates too much "
3c5f09422b69 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 "(computed %g, expected %g)" % (name, computed, expected))
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	90
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	91 NV_MAGICCONST = 4 * _exp(-0.5)/_sqrt(2.0)
21049 fed5071da957 SF patch 483059: Avoid use of eval() in random.py, from Finn Bock. Tim Peters <tim.peters@gmail.com> parents: 16616 diff changeset	92 _verify('NV_MAGICCONST', NV_MAGICCONST, 1.71552776992141)
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
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	94 TWOPI = 2.0*_pi
21049 fed5071da957 SF patch 483059: Avoid use of eval() in random.py, from Finn Bock. Tim Peters <tim.peters@gmail.com> parents: 16616 diff changeset	95 _verify('TWOPI', TWOPI, 6.28318530718)
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	96
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	97 LOG4 = _log(4.0)
21049 fed5071da957 SF patch 483059: Avoid use of eval() in random.py, from Finn Bock. Tim Peters <tim.peters@gmail.com> parents: 16616 diff changeset	98 _verify('LOG4', LOG4, 1.38629436111989)
8393 7669ddf0e7d4 Add Interfaces to replace remaining needs for importing whrandom. Guido van Rossum <guido@python.org> parents: 7881 diff changeset	99
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	100 SG_MAGICCONST = 1.0 + _log(4.5)
21049 fed5071da957 SF patch 483059: Avoid use of eval() in random.py, from Finn Bock. Tim Peters <tim.peters@gmail.com> parents: 16616 diff changeset	101 _verify('SG_MAGICCONST', SG_MAGICCONST, 2.50407739677627)
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	102
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	103 del _verify
8393 7669ddf0e7d4 Add Interfaces to replace remaining needs for importing whrandom. Guido van Rossum <guido@python.org> parents: 7881 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 # Translated by Guido van Rossum from C source provided by
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	106 # Adrian Baddeley.
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	107
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	108 class Random:
8393 7669ddf0e7d4 Add Interfaces to replace remaining needs for importing whrandom. Guido van Rossum <guido@python.org> parents: 7881 diff changeset	109
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	110 VERSION = 1 # used by getstate/setstate
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	111
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	112 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	113 """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	114
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	115 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	116 """
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	117
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	118 self.seed(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	119 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	120
16265 d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	121 ## -------------------- core generator -------------------
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	122
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	123 # Specific to Wichmann-Hill generator. Subclasses wishing to use a
16243 9fd96e2455b6 Fix bugs introduced by rewrite (in particular, time-based initialization Tim Peters <tim.peters@gmail.com> parents: 16242 diff changeset	124 # different core generator should override the seed(), random(),
16265 d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	125 # getstate(), setstate() and jumpahead() methods.
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	126
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	127 def seed(self, a=None):
5f0683a69efc Change random.seed() so that it can get at the full range of possible Tim Peters <tim.peters@gmail.com> parents: 16292 diff changeset	128 """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	129
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	130 None or no argument seeds from current time.
8393 7669ddf0e7d4 Add Interfaces to replace remaining needs for importing whrandom. Guido van Rossum <guido@python.org> parents: 7881 diff changeset	131
16386 c2555b4f38a3 Repaired a docstring. Tim Peters <tim.peters@gmail.com> parents: 16379 diff changeset	132 If a is not None or an int or long, hash(a) is used instead.
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	133
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	134 If a is an int or long, a is used directly. Distinct values between
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	135 0 and 27814431486575L inclusive are guaranteed to yield distinct
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	136 internal states (this guarantee is specific to the default
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	137 Wichmann-Hill generator).
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	138 """
8393 7669ddf0e7d4 Add Interfaces to replace remaining needs for importing whrandom. Guido van Rossum <guido@python.org> parents: 7881 diff changeset	139
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	140 if a 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	141 # Initialize from current time
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	142 import time
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	143 a = long(time.time() * 256)
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	144
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	145 if type(a) not in (type(3), type(3L)):
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	146 a = hash(a)
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	147
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	148 a, x = divmod(a, 30268)
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	149 a, y = divmod(a, 30306)
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	150 a, z = divmod(a, 30322)
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	151 self._seed = int(x)+1, int(y)+1, int(z)+1
8393 7669ddf0e7d4 Add Interfaces to replace remaining needs for importing whrandom. Guido van Rossum <guido@python.org> parents: 7881 diff changeset	152
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	153 def random(self):
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	154 """Get the next random number in the range [0.0, 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	155
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	156 # Wichman-Hill random number generator.
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	157 #
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	158 # Wichmann, B. A. & Hill, I. D. (1982)
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	159 # Algorithm AS 183:
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	160 # An efficient and portable pseudo-random number generator
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	161 # Applied Statistics 31 (1982) 188-190
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	162 #
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	163 # see also:
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	164 # Correction to Algorithm AS 183
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	165 # Applied Statistics 33 (1984) 123
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	166 #
3c5f09422b69 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 # McLeod, A. I. (1985)
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	168 # A remark on Algorithm AS 183
3c5f09422b69 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 # Applied Statistics 34 (1985),198-200
3c5f09422b69 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
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	171 # This part is thread-unsafe:
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	172 # BEGIN CRITICAL SECTION
3c5f09422b69 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 x, y, z = self._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	174 x = (171 * x) % 30269
3c5f09422b69 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 y = (172 * y) % 30307
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	176 z = (170 * z) % 30323
3c5f09422b69 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 self._seed = x, y, 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	178 # END CRITICAL SECTION
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	179
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	180 # Note: on a platform using IEEE-754 double arithmetic, this can
3c5f09422b69 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 # never return 0.0 (asserted by Tim; proof too long for a comment).
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	182 return (x/30269.0 + y/30307.0 + z/30323.0) % 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	183
16265 d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	184 def getstate(self):
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	185 """Return internal state; can be passed to setstate() later."""
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	186 return self.VERSION, self._seed, self.gauss_next
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	187
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	188 def setstate(self, state):
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	189 """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	190 version = state[0]
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	191 if version == 1:
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	192 version, self._seed, self.gauss_next = state
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	193 else:
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	194 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	195 "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	196 (version, self.VERSION))
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	197
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	198 def jumpahead(self, n):
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	199 """Act as if n calls to random() were made, but quickly.
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	200
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	201 n is an int, greater than or equal to 0.
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	202
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	203 Example use: If you have 2 threads and know that each will
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	204 consume no more than a million random numbers, create two Random
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	205 objects r1 and r2, then do
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	206 r2.setstate(r1.getstate())
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	207 r2.jumpahead(1000000)
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	208 Then r1 and r2 will use guaranteed-disjoint segments of the full
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	209 period.
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	210 """
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	211
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	212 if not n >= 0:
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	213 raise ValueError("n must be >= 0")
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	214 x, y, z = self._seed
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	215 x = int(x * pow(171, n, 30269)) % 30269
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	216 y = int(y * pow(172, n, 30307)) % 30307
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	217 z = int(z * pow(170, n, 30323)) % 30323
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	218 self._seed = x, y, z
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	219
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	220 def __whseed(self, x=0, y=0, z=0):
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	221 """Set the Wichmann-Hill seed from (x, y, z).
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	222
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	223 These must be integers in the range [0, 256).
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	224 """
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	225
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	226 if not type(x) == type(y) == type(z) == type(0):
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	227 raise TypeError('seeds must be integers')
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	228 if not (0 <= x < 256 and 0 <= y < 256 and 0 <= z < 256):
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	229 raise ValueError('seeds must be in range(0, 256)')
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	230 if 0 == x == y == z:
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	231 # Initialize from current time
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	232 import time
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	233 t = long(time.time() * 256)
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	234 t = int((t&0xffffff) ^ (t>>24))
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	235 t, x = divmod(t, 256)
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	236 t, y = divmod(t, 256)
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	237 t, z = divmod(t, 256)
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	238 # Zero is a poor seed, so substitute 1
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	239 self._seed = (x or 1, y or 1, z or 1)
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	240
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	241 def whseed(self, a=None):
5f0683a69efc Change random.seed() so that it can get at the full range of possible Tim Peters <tim.peters@gmail.com> parents: 16292 diff changeset	242 """Seed from hashable object's hash code.
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	243
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	244 None or no argument seeds from current time. It is not guaranteed
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	245 that objects with distinct hash codes lead to distinct internal
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	246 states.
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	247
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	248 This is obsolete, provided for compatibility with the seed routine
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	249 used prior to Python 2.1. Use the .seed() method instead.
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	250 """
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	251
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	252 if a is None:
5f0683a69efc Change random.seed() so that it can get at the full range of possible Tim Peters <tim.peters@gmail.com> parents: 16292 diff changeset	253 self.__whseed()
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	254 return
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	255 a = hash(a)
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	256 a, x = divmod(a, 256)
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	257 a, y = divmod(a, 256)
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	258 a, z = divmod(a, 256)
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	259 x = (x + a) % 256 or 1
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	260 y = (y + a) % 256 or 1
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	261 z = (z + a) % 256 or 1
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	262 self.__whseed(x, y, z)
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	263
16265 d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	264 ## ---- 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	265 ## ---- 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	266
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	267 ## -------------------- pickle support -------------------
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	268
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	269 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	270 return self.getstate()
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	271
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	272 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	273 self.setstate(state)
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	274
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	275 ## -------------------- integer methods -------------------
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	276
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	277 def randrange(self, start, stop=None, step=1, int=int, default=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	278 """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	279
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	280 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	281 endpoint; in Python this is usually not what you want.
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	282 Do not supply the 'int' and 'default' arguments.
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	283 """
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	284
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	285 # This code is a bit messy to make it fast for 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	286 # common case while still doing adequate error checking
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	287 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	288 if istart != start:
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	289 raise ValueError, "non-integer arg 1 for randrange()"
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	290 if stop is default:
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	291 if istart > 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	292 return int(self.random() * istart)
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	293 raise ValueError, "empty range for randrange()"
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	294 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	295 if istop != stop:
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	296 raise ValueError, "non-integer stop for randrange()"
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	297 if step == 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	298 if istart < istop:
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	299 return istart + int(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	300 (istop - istart))
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	301 raise ValueError, "empty range for randrange()"
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	302 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	303 if istep != step:
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	304 raise ValueError, "non-integer step for randrange()"
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	305 if istep > 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	306 n = (istop - istart + istep - 1) / istep
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	307 elif istep < 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	308 n = (istop - istart + istep + 1) / istep
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	309 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	310 raise ValueError, "zero step for randrange()"
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	311
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	312 if n <= 0:
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	313 raise ValueError, "empty range for randrange()"
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	314 return istart + istepint(self.random() n)
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	315
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	316 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	317 """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	318
16265 d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	319 (Deprecated; use randrange(a, b+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	320 """
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	321
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	322 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	323
16265 d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	324 ## -------------------- sequence methods -------------------
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	325
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	326 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	327 """Choose a random element from a non-empty sequence."""
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	328 return seq[int(self.random() * len(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	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 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	331 """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	332
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	333 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	334 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	335
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	336 Note that for even rather small len(x), the total number of
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	337 permutations of x is larger than the period of most random number
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	338 generators; this implies that "most" permutations of a long
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	339 sequence can never be generated.
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	340 """
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	341
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	342 if random is None:
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	343 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	344 for i in xrange(len(x)-1, 0, -1):
16265 d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	345 # pick an element in x[:i+1] with which to exchange x[i]
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	346 j = int(random() * (i+1))
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	347 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	348
16265 d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	349 ## -------------------- real-valued distributions -------------------
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	350
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	351 ## -------------------- 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	352
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	353 def uniform(self, a, b):
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	354 """Get a random number in the range [a, b)."""
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	355 return a + (b-a) * self.random()
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	356
16265 d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	357 ## -------------------- normal distribution --------------------
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	358
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	359 def normalvariate(self, mu, sigma):
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	360 # 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	361
3c5f09422b69 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 # 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	363 # 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	364 # 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	365 # Math Software, 3, (1977), pp257-260.
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	366
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	367 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	368 while 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	369 u1 = 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	370 u2 = 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	371 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	372 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	373 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	374 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	375 return mu + z*sigma
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	376
16265 d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	377 ## -------------------- lognormal distribution --------------------
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	378
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	379 def lognormvariate(self, mu, sigma):
3c5f09422b69 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 return _exp(self.normalvariate(mu, sigma))
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	381
16265 d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	382 ## -------------------- circular uniform --------------------
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	383
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	384 def cunifvariate(self, mean, arc):
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	385 # mean: mean angle (in radians between 0 and 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	386 # arc: range of distribution (in radians between 0 and pi)
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: 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 (mean + arc * (self.random() - 0.5)) % _pi
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):
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	393 # 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	394 # ('lambda' is a Python reserved word)
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	395
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	396 random = self.random
15871 62aeefa01fdd Whitespace normalization. Tim Peters <tim.peters@gmail.com> parents: 14617 diff changeset	397 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	398 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	399 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	400 return -_log(u)/lambd
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	401
16265 d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	402 ## -------------------- von Mises distribution --------------------
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	403
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	404 def vonmisesvariate(self, mu, 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	405 # 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	406 # 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	407 # if kappa = 0 generate uniform random angle
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	408
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	409 # 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	410 # "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	411 # 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	412
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	413 # 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	414 # 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	415
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	416 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	417 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	418 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	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 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	421 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	422 r = (1.0 + b * b)/(2.0 * b)
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 while 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	425 u1 = random()
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	426
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	427 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	428 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	429 c = kappa * (r - f)
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: 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 u2 = random()
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	432
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	433 if not (u2 >= c * (2.0 - c) and u2 > c * _exp(1.0 - c)):
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	434 break
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	435
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	436 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	437 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	438 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	439 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	440 theta = (mu % TWOPI) - _acos(f)
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 return theta
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	443
16265 d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	444 ## -------------------- gamma distribution --------------------
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 def gammavariate(self, alpha, beta):
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	447 # beta times standard 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	448 ainv = _sqrt(2.0 * 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	449 return beta * self.stdgamma(alpha, ainv, alpha - LOG4, alpha + ainv)
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 def stdgamma(self, alpha, ainv, bbb, ccc):
3c5f09422b69 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 # ainv = sqrt(2 * alpha - 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	453 # bbb = alpha - log(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	454 # ccc = alpha + ainv
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	455
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	456 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	457 if alpha <= 0.0:
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	458 raise ValueError, 'stdgamma: alpha must be > 0.0'
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	459
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	460 if alpha > 1.0:
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	461
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	462 # 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	463 # 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	464 # Applied Statistics, (1977), 26, No. 1, p71-74
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	465
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	466 while 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	467 u1 = 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	468 u2 = 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	469 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	470 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	471 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	472 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	473 if r + SG_MAGICCONST - 4.5*z >= 0.0 or r >= _log(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	474 return x
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	475
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	476 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	477 # expovariate(1)
15871 62aeefa01fdd Whitespace normalization. Tim Peters <tim.peters@gmail.com> parents: 14617 diff changeset	478 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	479 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	480 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	481 return -_log(u)
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	482
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	483 else: # alpha is between 0 and 1 (exclusive)
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	484
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	485 # Uses ALGORITHM GS of Statistical Computing - Kennedy & Gentle
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	486
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	487 while 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	488 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	489 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	490 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	491 if p <= 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	492 x = pow(p, 1.0/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	493 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	494 # p > 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	495 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	496 u1 = 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	497 if not (((p <= 1.0) and (u1 > _exp(-x))) or
3c5f09422b69 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 ((p > 1) and (u1 > pow(x, 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	499 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	500 return x
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	501
1576 695fb494a3a2 Added gauss() (same as normal but twice as fast) and betavariate(); Guido van Rossum <guido@python.org> parents: 1575 diff changeset	502
16265 d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	503 ## -------------------- 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	504
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	505 def gauss(self, mu, sigma):
1577 444e349f962f Use float constants directly; cosmetic changes; initialize largest Guido van Rossum <guido@python.org> parents: 1576 diff changeset	506
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 # 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	508 # 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	509 #
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	510 # 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	511 # 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	512 #
3c5f09422b69 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 # 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	514 # (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	515 # (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	516 # (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	517
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	518 # 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	519 # 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	520 # 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	521 # 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	522 # 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	523 # lock here.)
1577 444e349f962f Use float constants directly; cosmetic changes; initialize largest Guido van Rossum <guido@python.org> parents: 1576 diff changeset	524
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	525 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	526 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	527 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	528 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	529 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	530 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	531 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	532 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	533
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	534 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	535
16265 d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	536 ## -------------------- beta --------------------
16271 7ef2382f6123 SF bug 130030: Claim of bad betavariate algorithm. Tim Peters <tim.peters@gmail.com> parents: 16265 diff changeset	537 ## See
7ef2382f6123 SF bug 130030: Claim of bad betavariate algorithm. Tim Peters <tim.peters@gmail.com> parents: 16265 diff changeset	538 ## http://sourceforge.net/bugs/?func=detailbug&bug_id=130030&group_id=5470
7ef2382f6123 SF bug 130030: Claim of bad betavariate algorithm. Tim Peters <tim.peters@gmail.com> parents: 16265 diff changeset	539 ## 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	540 ##
7ef2382f6123 SF bug 130030: Claim of bad betavariate algorithm. Tim Peters <tim.peters@gmail.com> parents: 16265 diff changeset	541 ## def betavariate(self, alpha, beta):
7ef2382f6123 SF bug 130030: Claim of bad betavariate algorithm. Tim Peters <tim.peters@gmail.com> parents: 16265 diff changeset	542 ## # 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	543 ##
7ef2382f6123 SF bug 130030: Claim of bad betavariate algorithm. Tim Peters <tim.peters@gmail.com> parents: 16265 diff changeset	544 ## y = self.expovariate(alpha)
7ef2382f6123 SF bug 130030: Claim of bad betavariate algorithm. Tim Peters <tim.peters@gmail.com> parents: 16265 diff changeset	545 ## 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	546 ## return z/(y+z)
7ef2382f6123 SF bug 130030: Claim of bad betavariate algorithm. Tim Peters <tim.peters@gmail.com> parents: 16265 diff changeset	547 ##
7ef2382f6123 SF bug 130030: Claim of bad betavariate algorithm. Tim Peters <tim.peters@gmail.com> parents: 16265 diff changeset	548 ## 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	549
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	550 def betavariate(self, alpha, beta):
16271 7ef2382f6123 SF bug 130030: Claim of bad betavariate algorithm. Tim Peters <tim.peters@gmail.com> parents: 16265 diff changeset	551 # 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	552 # 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	553 y = self.gammavariate(alpha, 1.)
7ef2382f6123 SF bug 130030: Claim of bad betavariate algorithm. Tim Peters <tim.peters@gmail.com> parents: 16265 diff changeset	554 if y == 0:
7ef2382f6123 SF bug 130030: Claim of bad betavariate algorithm. Tim Peters <tim.peters@gmail.com> parents: 16265 diff changeset	555 return 0.0
7ef2382f6123 SF bug 130030: Claim of bad betavariate algorithm. Tim Peters <tim.peters@gmail.com> parents: 16265 diff changeset	556 else:
7ef2382f6123 SF bug 130030: Claim of bad betavariate algorithm. Tim Peters <tim.peters@gmail.com> parents: 16265 diff changeset	557 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	558
16265 d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	559 ## -------------------- Pareto --------------------
6698 b73eb4e6face Added Pareto and Weibull distributions, courtesy Jeremy Hylton. Guido van Rossum <guido@python.org> parents: 1618 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 def paretovariate(self, 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	562 # Jain, pg. 495
6698 b73eb4e6face Added Pareto and Weibull distributions, courtesy Jeremy Hylton. Guido van Rossum <guido@python.org> parents: 1618 diff changeset	563
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	564 u = 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	565 return 1.0 / pow(u, 1.0/alpha)
6698 b73eb4e6face Added Pareto and Weibull distributions, courtesy Jeremy Hylton. Guido van Rossum <guido@python.org> parents: 1618 diff changeset	566
16265 d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	567 ## -------------------- Weibull --------------------
6698 b73eb4e6face Added Pareto and Weibull distributions, courtesy Jeremy Hylton. Guido van Rossum <guido@python.org> parents: 1618 diff changeset	568
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	569 def weibullvariate(self, alpha, beta):
3c5f09422b69 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 # 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	571
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	572 u = 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	573 return alpha * pow(-_log(u), 1.0/beta)
11200 bca2d14f3e36 Add Tim Peters' shuffle() algorithm. Guido van Rossum <guido@python.org> parents: 8802 diff changeset	574
16265 d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	575 ## -------------------- test program --------------------
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	576
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	577 def _test_generator(n, funccall):
15871 62aeefa01fdd Whitespace normalization. Tim Peters <tim.peters@gmail.com> parents: 14617 diff changeset	578 import time
62aeefa01fdd Whitespace normalization. Tim Peters <tim.peters@gmail.com> parents: 14617 diff changeset	579 print n, 'times', funccall
62aeefa01fdd Whitespace normalization. Tim Peters <tim.peters@gmail.com> parents: 14617 diff changeset	580 code = compile(funccall, funccall, 'eval')
62aeefa01fdd Whitespace normalization. Tim Peters <tim.peters@gmail.com> parents: 14617 diff changeset	581 sum = 0.0
62aeefa01fdd Whitespace normalization. Tim Peters <tim.peters@gmail.com> parents: 14617 diff changeset	582 sqsum = 0.0
62aeefa01fdd Whitespace normalization. Tim Peters <tim.peters@gmail.com> parents: 14617 diff changeset	583 smallest = 1e10
62aeefa01fdd Whitespace normalization. Tim Peters <tim.peters@gmail.com> parents: 14617 diff changeset	584 largest = -1e10
62aeefa01fdd Whitespace normalization. Tim Peters <tim.peters@gmail.com> parents: 14617 diff changeset	585 t0 = time.time()
62aeefa01fdd Whitespace normalization. Tim Peters <tim.peters@gmail.com> parents: 14617 diff changeset	586 for i in range(n):
62aeefa01fdd Whitespace normalization. Tim Peters <tim.peters@gmail.com> parents: 14617 diff changeset	587 x = eval(code)
62aeefa01fdd Whitespace normalization. Tim Peters <tim.peters@gmail.com> parents: 14617 diff changeset	588 sum = sum + x
62aeefa01fdd Whitespace normalization. Tim Peters <tim.peters@gmail.com> parents: 14617 diff changeset	589 sqsum = sqsum + x*x
62aeefa01fdd Whitespace normalization. Tim Peters <tim.peters@gmail.com> parents: 14617 diff changeset	590 smallest = min(x, smallest)
62aeefa01fdd Whitespace normalization. Tim Peters <tim.peters@gmail.com> parents: 14617 diff changeset	591 largest = max(x, largest)
62aeefa01fdd Whitespace normalization. Tim Peters <tim.peters@gmail.com> parents: 14617 diff changeset	592 t1 = time.time()
62aeefa01fdd Whitespace normalization. Tim Peters <tim.peters@gmail.com> parents: 14617 diff changeset	593 print round(t1-t0, 3), 'sec,',
62aeefa01fdd Whitespace normalization. Tim Peters <tim.peters@gmail.com> parents: 14617 diff changeset	594 avg = sum/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	595 stddev = _sqrt(sqsum/n - avg*avg)
15871 62aeefa01fdd Whitespace normalization. Tim Peters <tim.peters@gmail.com> parents: 14617 diff changeset	596 print 'avg %g, stddev %g, min %g, max %g' % \
62aeefa01fdd Whitespace normalization. Tim Peters <tim.peters@gmail.com> parents: 14617 diff changeset	597 (avg, stddev, smallest, largest)
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	598
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	599 def _test(N=200):
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	600 print 'TWOPI =', 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	601 print 'LOG4 =', LOG4
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	602 print 'NV_MAGICCONST =', NV_MAGICCONST
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	603 print 'SG_MAGICCONST =', SG_MAGICCONST
3c5f09422b69 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 _test_generator(N, '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	605 _test_generator(N, 'normalvariate(0.0, 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	606 _test_generator(N, 'lognormvariate(0.0, 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	607 _test_generator(N, 'cunifvariate(0.0, 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	608 _test_generator(N, 'expovariate(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	609 _test_generator(N, 'vonmisesvariate(0.0, 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	610 _test_generator(N, 'gammavariate(0.5, 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	611 _test_generator(N, 'gammavariate(0.9, 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	612 _test_generator(N, 'gammavariate(1.0, 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	613 _test_generator(N, 'gammavariate(2.0, 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	614 _test_generator(N, 'gammavariate(20.0, 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	615 _test_generator(N, 'gammavariate(200.0, 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	616 _test_generator(N, 'gauss(0.0, 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	617 _test_generator(N, 'betavariate(3.0, 3.0)')
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	618 _test_generator(N, 'paretovariate(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	619 _test_generator(N, 'weibullvariate(1.0, 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	620
16265 d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	621 # Test jumpahead.
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	622 s = getstate()
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	623 jumpahead(N)
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	624 r1 = random()
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	625 # now do it the slow way
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	626 setstate(s)
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	627 for i in range(N):
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	628 random()
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	629 r2 = random()
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	630 if r1 != r2:
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	631 raise ValueError("jumpahead test failed " + `(N, r1, r2)`)
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	632
16292 0501c2a10315 New comment block to Clarify a subtlety. Tim Peters <tim.peters@gmail.com> parents: 16272 diff changeset	633 # Create one instance, seeded from current time, and export its methods
0501c2a10315 New comment block to Clarify a subtlety. Tim Peters <tim.peters@gmail.com> parents: 16272 diff changeset	634 # as module-level functions. The functions are not threadsafe, and state
0501c2a10315 New comment block to Clarify a subtlety. Tim Peters <tim.peters@gmail.com> parents: 16272 diff changeset	635 # is shared across all uses (both in the user's code and in the Python
0501c2a10315 New comment block to Clarify a subtlety. Tim Peters <tim.peters@gmail.com> parents: 16272 diff changeset	636 # libraries), but that's fine for most programs and is easier for the
0501c2a10315 New comment block to Clarify a subtlety. Tim Peters <tim.peters@gmail.com> parents: 16272 diff changeset	637 # casual user than making them instantiate their own Random() instance.
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	638 _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	639 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	640 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	641 uniform = _inst.uniform
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	642 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	643 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	644 randrange = _inst.randrange
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	645 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	646 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	647 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	648 cunifvariate = _inst.cunifvariate
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	649 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	650 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	651 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	652 stdgamma = _inst.stdgamma
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	653 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	654 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	655 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	656 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	657 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	658 setstate = _inst.setstate
16243 9fd96e2455b6 Fix bugs introduced by rewrite (in particular, time-based initialization Tim Peters <tim.peters@gmail.com> parents: 16242 diff changeset	659 jumpahead = _inst.jumpahead
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	660 whseed = _inst.whseed
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	661
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	662 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	663 _test()

Mercurial > cpython-lru_cache-weakref

annotate Lib/random.py @ 22360:c8a6ea00a9e1 legacy-trunk