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

annotate Lib/random.py @ 25838:8540887bcec6 2.2

Backport of 2.183: Fix memory leak in add_subclass() found by NealN with valgrind.

author	Guido van Rossum <guido@python.org>
date	Fri, 18 Oct 2002 13:42:21 +0000
parents	276b6c452999
children	38319409e895

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
25359 3f5041295448 Backport: Raymond Hettinger <python@rcn.com> parents: 25358 diff changeset	78 from math import floor as _floor
8455 af9273b1073a Make gauss() semi-thread-safe. It can still give duplicate results, Guido van Rossum <guido@python.org> parents: 8393 diff changeset	79
16613 f68dbffff927 bunch more __all__ lists Skip Montanaro <skip@pobox.com> parents: 16386 diff changeset	80 __all__ = ["Random","seed","random","uniform","randint","choice",
f68dbffff927 bunch more __all__ lists Skip Montanaro <skip@pobox.com> parents: 16386 diff changeset	81 "randrange","shuffle","normalvariate","lognormvariate",
f68dbffff927 bunch more __all__ lists Skip Montanaro <skip@pobox.com> parents: 16386 diff changeset	82 "cunifvariate","expovariate","vonmisesvariate","gammavariate",
f68dbffff927 bunch more __all__ lists Skip Montanaro <skip@pobox.com> parents: 16386 diff changeset	83 "stdgamma","gauss","betavariate","paretovariate","weibullvariate",
f68dbffff927 bunch more __all__ lists Skip Montanaro <skip@pobox.com> parents: 16386 diff changeset	84 "getstate","setstate","jumpahead","whseed"]
16616 e2a63584566f Whitespace normalization. Tim Peters <tim.peters@gmail.com> parents: 16613 diff changeset	85
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	86 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	87 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	88 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	89 "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	90 "(computed %g, expected %g)" % (name, computed, expected))
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	91
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	92 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	93 _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	94
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	95 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	96 _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	97
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	98 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	99 _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	100
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	101 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	102 _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	103
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	104 del _verify
8393 7669ddf0e7d4 Add Interfaces to replace remaining needs for importing whrandom. Guido van Rossum <guido@python.org> parents: 7881 diff changeset	105
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	106 # 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	107 # 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	108
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	109 class Random:
25581 276b6c452999 Backport 1.33 (omitting the deprecation warning but keeping the deprecation Raymond Hettinger <python@rcn.com> parents: 25359 diff changeset	110 """Random number generator base class used by bound module functions.
276b6c452999 Backport 1.33 (omitting the deprecation warning but keeping the deprecation Raymond Hettinger <python@rcn.com> parents: 25359 diff changeset	111
276b6c452999 Backport 1.33 (omitting the deprecation warning but keeping the deprecation Raymond Hettinger <python@rcn.com> parents: 25359 diff changeset	112 Used to instantiate instances of Random to get generators that don't
276b6c452999 Backport 1.33 (omitting the deprecation warning but keeping the deprecation Raymond Hettinger <python@rcn.com> parents: 25359 diff changeset	113 share state. Especially useful for multi-threaded programs, creating
276b6c452999 Backport 1.33 (omitting the deprecation warning but keeping the deprecation Raymond Hettinger <python@rcn.com> parents: 25359 diff changeset	114 a different instance of Random for each thread, and using the jumpahead()
276b6c452999 Backport 1.33 (omitting the deprecation warning but keeping the deprecation Raymond Hettinger <python@rcn.com> parents: 25359 diff changeset	115 method to ensure that the generated sequences seen by each thread don't
276b6c452999 Backport 1.33 (omitting the deprecation warning but keeping the deprecation Raymond Hettinger <python@rcn.com> parents: 25359 diff changeset	116 overlap.
276b6c452999 Backport 1.33 (omitting the deprecation warning but keeping the deprecation Raymond Hettinger <python@rcn.com> parents: 25359 diff changeset	117
276b6c452999 Backport 1.33 (omitting the deprecation warning but keeping the deprecation Raymond Hettinger <python@rcn.com> parents: 25359 diff changeset	118 Class Random can also be subclassed if you want to use a different basic
276b6c452999 Backport 1.33 (omitting the deprecation warning but keeping the deprecation Raymond Hettinger <python@rcn.com> parents: 25359 diff changeset	119 generator of your own devising: in that case, override the following
276b6c452999 Backport 1.33 (omitting the deprecation warning but keeping the deprecation Raymond Hettinger <python@rcn.com> parents: 25359 diff changeset	120 methods: random(), seed(), getstate(), setstate() and jumpahead().
276b6c452999 Backport 1.33 (omitting the deprecation warning but keeping the deprecation Raymond Hettinger <python@rcn.com> parents: 25359 diff changeset	121
276b6c452999 Backport 1.33 (omitting the deprecation warning but keeping the deprecation Raymond Hettinger <python@rcn.com> parents: 25359 diff changeset	122 """
8393 7669ddf0e7d4 Add Interfaces to replace remaining needs for importing whrandom. Guido van Rossum <guido@python.org> parents: 7881 diff changeset	123
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	124 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	125
3c5f09422b69 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 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	127 """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	128
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	129 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	130 """
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	131
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	132 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	133
16265 d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	134 ## -------------------- core generator -------------------
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	135
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	136 # 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	137 # 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	138 # 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	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 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	141 """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	142
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 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	144
16386 c2555b4f38a3 Repaired a docstring. Tim Peters <tim.peters@gmail.com> parents: 16379 diff changeset	145 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	146
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 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	148 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	149 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	150 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	151 """
8393 7669ddf0e7d4 Add Interfaces to replace remaining needs for importing whrandom. Guido van Rossum <guido@python.org> parents: 7881 diff changeset	152
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	153 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	154 # 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	155 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	156 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	157
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	158 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	159 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	160
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	161 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	162 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	163 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	164 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	165
25358 0fbb76b5074b Whitespace normalization and backport: Raymond Hettinger <python@rcn.com> parents: 23450 diff changeset	166 self.gauss_next = None
0fbb76b5074b Whitespace normalization and backport: Raymond Hettinger <python@rcn.com> parents: 23450 diff changeset	167
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	168 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	169 """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	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 # 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	172 #
3c5f09422b69 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 # 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	174 # 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	175 # 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	176 # 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	177 #
3c5f09422b69 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 # 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	179 # 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	180 # 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	181 #
3c5f09422b69 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 # 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	183 # 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	184 # 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	185
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	186 # 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	187 # 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	188 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	189 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	190 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	191 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	192 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	193 # 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	194
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	195 # 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	196 # 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	197 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	198
16265 d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	199 def getstate(self):
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	200 """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	201 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	202
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	203 def setstate(self, state):
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	204 """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	205 version = state[0]
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	206 if version == 1:
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	207 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	208 else:
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	209 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	210 "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	211 (version, self.VERSION))
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	212
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	213 def jumpahead(self, n):
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	214 """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	215
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	216 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	217
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	218 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	219 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	220 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	221 r2.setstate(r1.getstate())
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	222 r2.jumpahead(1000000)
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	223 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	224 period.
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	225 """
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	226
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	227 if not n >= 0:
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	228 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	229 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	230 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	231 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	232 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	233 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	234
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	235 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	236 """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	237
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 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	239 """
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 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	242 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	243 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	244 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	245 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	246 # 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	247 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	248 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	249 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	250 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	251 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	252 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	253 # 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	254 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	255
25358 0fbb76b5074b Whitespace normalization and backport: Raymond Hettinger <python@rcn.com> parents: 23450 diff changeset	256 self.gauss_next = None
0fbb76b5074b Whitespace normalization and backport: Raymond Hettinger <python@rcn.com> parents: 23450 diff changeset	257
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	258 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	259 """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	260
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 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	262 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	263 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	264
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	265 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	266 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	267 """
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	268
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	269 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	270 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	271 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	272 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	273 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	274 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	275 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	276 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	277 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	278 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	279 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	280
16265 d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	281 ## ---- 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	282 ## ---- 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	283
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	284 ## -------------------- pickle support -------------------
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	285
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	286 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	287 return self.getstate()
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	288
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	289 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	290 self.setstate(state)
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	291
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	292 ## -------------------- integer methods -------------------
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	293
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	294 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	295 """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	296
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	297 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	298 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	299 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	300 """
3c5f09422b69 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
3c5f09422b69 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 # This code is a bit messy to make it fast for the
25359 3f5041295448 Backport: Raymond Hettinger <python@rcn.com> parents: 25358 diff changeset	303 # common case while still doing adequate error checking.
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	304 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	305 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	306 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	307 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	308 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	309 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	310 raise ValueError, "empty range for randrange()"
25359 3f5041295448 Backport: Raymond Hettinger <python@rcn.com> parents: 25358 diff changeset	311
3f5041295448 Backport: Raymond Hettinger <python@rcn.com> parents: 25358 diff changeset	312 # stop argument supplied.
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	313 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	314 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	315 raise ValueError, "non-integer stop for randrange()"
25359 3f5041295448 Backport: Raymond Hettinger <python@rcn.com> parents: 25358 diff changeset	316 if step == 1 and istart < istop:
3f5041295448 Backport: Raymond Hettinger <python@rcn.com> parents: 25358 diff changeset	317 try:
3f5041295448 Backport: Raymond Hettinger <python@rcn.com> parents: 25358 diff changeset	318 return istart + int(self.random()*(istop - istart))
3f5041295448 Backport: Raymond Hettinger <python@rcn.com> parents: 25358 diff changeset	319 except OverflowError:
3f5041295448 Backport: Raymond Hettinger <python@rcn.com> parents: 25358 diff changeset	320 # This can happen if istop-istart > sys.maxint + 1, and
3f5041295448 Backport: Raymond Hettinger <python@rcn.com> parents: 25358 diff changeset	321 # multiplying by random() doesn't reduce it to something
3f5041295448 Backport: Raymond Hettinger <python@rcn.com> parents: 25358 diff changeset	322 # <= sys.maxint. We know that the overall result fits
3f5041295448 Backport: Raymond Hettinger <python@rcn.com> parents: 25358 diff changeset	323 # in an int, and can still do it correctly via math.floor().
3f5041295448 Backport: Raymond Hettinger <python@rcn.com> parents: 25358 diff changeset	324 # But that adds another function call, so for speed we
3f5041295448 Backport: Raymond Hettinger <python@rcn.com> parents: 25358 diff changeset	325 # avoided that whenever possible.
3f5041295448 Backport: Raymond Hettinger <python@rcn.com> parents: 25358 diff changeset	326 return int(istart + _floor(self.random()*(istop - istart)))
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	327 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	328 raise ValueError, "empty range for randrange()"
25359 3f5041295448 Backport: Raymond Hettinger <python@rcn.com> parents: 25358 diff changeset	329
3f5041295448 Backport: Raymond Hettinger <python@rcn.com> parents: 25358 diff changeset	330 # Non-unit step argument supplied.
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	331 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	332 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	333 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	334 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	335 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	336 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	337 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	338 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	339 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	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 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	342 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	343 return istart + istepint(self.random() n)
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	344
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	345 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	346 """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	347 """
3c5f09422b69 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
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	349 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	350
16265 d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	351 ## -------------------- sequence methods -------------------
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	352
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	353 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	354 """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	355 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	356
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	357 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	358 """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	359
3c5f09422b69 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 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	361 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	362
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	363 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	364 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	365 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	366 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	367 """
3c5f09422b69 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
3c5f09422b69 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 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	370 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	371 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	372 # 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	373 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	374 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	375
16265 d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	376 ## -------------------- real-valued distributions -------------------
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	377
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	378 ## -------------------- 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	379
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	380 def 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	381 """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	382 return a + (b-a) * self.random()
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	383
16265 d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	384 ## -------------------- normal distribution --------------------
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	385
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	386 def normalvariate(self, mu, sigma):
25581 276b6c452999 Backport 1.33 (omitting the deprecation warning but keeping the deprecation Raymond Hettinger <python@rcn.com> parents: 25359 diff changeset	387 """Normal distribution.
276b6c452999 Backport 1.33 (omitting the deprecation warning but keeping the deprecation Raymond Hettinger <python@rcn.com> parents: 25359 diff changeset	388
276b6c452999 Backport 1.33 (omitting the deprecation warning but keeping the deprecation Raymond Hettinger <python@rcn.com> parents: 25359 diff changeset	389 mu is the mean, and sigma is the standard deviation.
276b6c452999 Backport 1.33 (omitting the deprecation warning but keeping the deprecation Raymond Hettinger <python@rcn.com> parents: 25359 diff changeset	390
276b6c452999 Backport 1.33 (omitting the deprecation warning but keeping the deprecation Raymond Hettinger <python@rcn.com> parents: 25359 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 # 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	393
3c5f09422b69 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 # 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	395 # 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	396 # 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	397 # Math Software, 3, (1977), pp257-260.
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	398
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	399 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	400 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	401 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	402 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	403 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	404 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	405 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	406 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	407 return mu + z*sigma
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	408
16265 d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	409 ## -------------------- lognormal distribution --------------------
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	410
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	411 def lognormvariate(self, mu, sigma):
25581 276b6c452999 Backport 1.33 (omitting the deprecation warning but keeping the deprecation Raymond Hettinger <python@rcn.com> parents: 25359 diff changeset	412 """Log normal distribution.
276b6c452999 Backport 1.33 (omitting the deprecation warning but keeping the deprecation Raymond Hettinger <python@rcn.com> parents: 25359 diff changeset	413
276b6c452999 Backport 1.33 (omitting the deprecation warning but keeping the deprecation Raymond Hettinger <python@rcn.com> parents: 25359 diff changeset	414 If you take the natural logarithm of this distribution, you'll get a
276b6c452999 Backport 1.33 (omitting the deprecation warning but keeping the deprecation Raymond Hettinger <python@rcn.com> parents: 25359 diff changeset	415 normal distribution with mean mu and standard deviation sigma.
276b6c452999 Backport 1.33 (omitting the deprecation warning but keeping the deprecation Raymond Hettinger <python@rcn.com> parents: 25359 diff changeset	416 mu can have any value, and sigma must be greater than zero.
276b6c452999 Backport 1.33 (omitting the deprecation warning but keeping the deprecation Raymond Hettinger <python@rcn.com> parents: 25359 diff changeset	417
276b6c452999 Backport 1.33 (omitting the deprecation warning but keeping the deprecation Raymond Hettinger <python@rcn.com> parents: 25359 diff changeset	418 """
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	419 return _exp(self.normalvariate(mu, sigma))
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	420
16265 d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	421 ## -------------------- circular uniform --------------------
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	422
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	423 def cunifvariate(self, mean, arc):
25581 276b6c452999 Backport 1.33 (omitting the deprecation warning but keeping the deprecation Raymond Hettinger <python@rcn.com> parents: 25359 diff changeset	424 """Circular uniform distribution.
276b6c452999 Backport 1.33 (omitting the deprecation warning but keeping the deprecation Raymond Hettinger <python@rcn.com> parents: 25359 diff changeset	425
276b6c452999 Backport 1.33 (omitting the deprecation warning but keeping the deprecation Raymond Hettinger <python@rcn.com> parents: 25359 diff changeset	426 mean is the mean angle, and arc is the range of the distribution,
276b6c452999 Backport 1.33 (omitting the deprecation warning but keeping the deprecation Raymond Hettinger <python@rcn.com> parents: 25359 diff changeset	427 centered around the mean angle. Both values must be expressed in
276b6c452999 Backport 1.33 (omitting the deprecation warning but keeping the deprecation Raymond Hettinger <python@rcn.com> parents: 25359 diff changeset	428 radians. Returned values range between mean - arc/2 and
276b6c452999 Backport 1.33 (omitting the deprecation warning but keeping the deprecation Raymond Hettinger <python@rcn.com> parents: 25359 diff changeset	429 mean + arc/2 and are normalized to between 0 and pi.
276b6c452999 Backport 1.33 (omitting the deprecation warning but keeping the deprecation Raymond Hettinger <python@rcn.com> parents: 25359 diff changeset	430
276b6c452999 Backport 1.33 (omitting the deprecation warning but keeping the deprecation Raymond Hettinger <python@rcn.com> parents: 25359 diff changeset	431 Deprecated in version 2.3. Use:
276b6c452999 Backport 1.33 (omitting the deprecation warning but keeping the deprecation Raymond Hettinger <python@rcn.com> parents: 25359 diff changeset	432 (mean + arc * (Random.random() - 0.5)) % Math.pi
276b6c452999 Backport 1.33 (omitting the deprecation warning but keeping the deprecation Raymond Hettinger <python@rcn.com> parents: 25359 diff changeset	433
276b6c452999 Backport 1.33 (omitting the deprecation warning but keeping the deprecation Raymond Hettinger <python@rcn.com> parents: 25359 diff changeset	434 """
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	435 # 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	436 # arc: range of distribution (in radians between 0 and pi)
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	437
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	438 return (mean + arc * (self.random() - 0.5)) % _pi
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	439
16265 d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	440 ## -------------------- exponential distribution --------------------
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 def expovariate(self, lambd):
25581 276b6c452999 Backport 1.33 (omitting the deprecation warning but keeping the deprecation Raymond Hettinger <python@rcn.com> parents: 25359 diff changeset	443 """Exponential distribution.
276b6c452999 Backport 1.33 (omitting the deprecation warning but keeping the deprecation Raymond Hettinger <python@rcn.com> parents: 25359 diff changeset	444
276b6c452999 Backport 1.33 (omitting the deprecation warning but keeping the deprecation Raymond Hettinger <python@rcn.com> parents: 25359 diff changeset	445 lambd is 1.0 divided by the desired mean. (The parameter would be
276b6c452999 Backport 1.33 (omitting the deprecation warning but keeping the deprecation Raymond Hettinger <python@rcn.com> parents: 25359 diff changeset	446 called "lambda", but that is a reserved word in Python.) Returned
276b6c452999 Backport 1.33 (omitting the deprecation warning but keeping the deprecation Raymond Hettinger <python@rcn.com> parents: 25359 diff changeset	447 values range from 0 to positive infinity.
276b6c452999 Backport 1.33 (omitting the deprecation warning but keeping the deprecation Raymond Hettinger <python@rcn.com> parents: 25359 diff changeset	448
276b6c452999 Backport 1.33 (omitting the deprecation warning but keeping the deprecation Raymond Hettinger <python@rcn.com> parents: 25359 diff changeset	449 """
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	450 # 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	451 # ('lambda' is a Python reserved word)
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	452
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	453 random = self.random
15871 62aeefa01fdd Whitespace normalization. Tim Peters <tim.peters@gmail.com> parents: 14617 diff changeset	454 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	455 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	456 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	457 return -_log(u)/lambd
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	458
16265 d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	459 ## -------------------- von Mises distribution --------------------
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	460
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	461 def vonmisesvariate(self, mu, kappa):
25581 276b6c452999 Backport 1.33 (omitting the deprecation warning but keeping the deprecation Raymond Hettinger <python@rcn.com> parents: 25359 diff changeset	462 """Circular data distribution.
276b6c452999 Backport 1.33 (omitting the deprecation warning but keeping the deprecation Raymond Hettinger <python@rcn.com> parents: 25359 diff changeset	463
276b6c452999 Backport 1.33 (omitting the deprecation warning but keeping the deprecation Raymond Hettinger <python@rcn.com> parents: 25359 diff changeset	464 mu is the mean angle, expressed in radians between 0 and 2*pi, and
276b6c452999 Backport 1.33 (omitting the deprecation warning but keeping the deprecation Raymond Hettinger <python@rcn.com> parents: 25359 diff changeset	465 kappa is the concentration parameter, which must be greater than or
276b6c452999 Backport 1.33 (omitting the deprecation warning but keeping the deprecation Raymond Hettinger <python@rcn.com> parents: 25359 diff changeset	466 equal to zero. If kappa is equal to zero, this distribution reduces
276b6c452999 Backport 1.33 (omitting the deprecation warning but keeping the deprecation Raymond Hettinger <python@rcn.com> parents: 25359 diff changeset	467 to a uniform random angle over the range 0 to 2*pi.
276b6c452999 Backport 1.33 (omitting the deprecation warning but keeping the deprecation Raymond Hettinger <python@rcn.com> parents: 25359 diff changeset	468
276b6c452999 Backport 1.33 (omitting the deprecation warning but keeping the deprecation Raymond Hettinger <python@rcn.com> parents: 25359 diff changeset	469 """
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	470 # 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	471 # 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	472 # if kappa = 0 generate uniform random angle
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	473
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	474 # 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	475 # "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	476 # 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	477
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	478 # 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	479 # 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	480
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	481 random = self.random
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	482 if 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	483 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	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 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	486 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	487 r = (1.0 + b * b)/(2.0 * b)
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	488
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	489 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	490 u1 = random()
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	491
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	492 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	493 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	494 c = kappa * (r - f)
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	495
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	496 u2 = random()
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	497
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	498 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	499 break
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	500
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	501 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	502 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	503 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	504 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	505 theta = (mu % TWOPI) - _acos(f)
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: 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 return theta
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	508
16265 d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	509 ## -------------------- gamma distribution --------------------
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	510
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	511 def gammavariate(self, alpha, beta):
25581 276b6c452999 Backport 1.33 (omitting the deprecation warning but keeping the deprecation Raymond Hettinger <python@rcn.com> parents: 25359 diff changeset	512 """Gamma distribution. Not the gamma function!
276b6c452999 Backport 1.33 (omitting the deprecation warning but keeping the deprecation Raymond Hettinger <python@rcn.com> parents: 25359 diff changeset	513
276b6c452999 Backport 1.33 (omitting the deprecation warning but keeping the deprecation Raymond Hettinger <python@rcn.com> parents: 25359 diff changeset	514 Conditions on the parameters are alpha > 0 and beta > 0.
276b6c452999 Backport 1.33 (omitting the deprecation warning but keeping the deprecation Raymond Hettinger <python@rcn.com> parents: 25359 diff changeset	515
276b6c452999 Backport 1.33 (omitting the deprecation warning but keeping the deprecation Raymond Hettinger <python@rcn.com> parents: 25359 diff changeset	516 """
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	517
23448 453e59a472b2 Closes patch 529408 deprecating random.stdgamma(). Raymond Hettinger <python@rcn.com> parents: 23443 diff changeset	518 # alpha > 0, beta > 0, mean is alphabeta, variance is alphabeta**2
25358 0fbb76b5074b Whitespace normalization and backport: Raymond Hettinger <python@rcn.com> parents: 23450 diff changeset	519
23450 1cc93d501b45 Use spaces, not tabs for indents. Guido van Rossum <guido@python.org> parents: 23448 diff changeset	520 # Warning: a few older sources define the gamma distribution in terms
1cc93d501b45 Use spaces, not tabs for indents. Guido van Rossum <guido@python.org> parents: 23448 diff changeset	521 # of alpha > -1.0
1cc93d501b45 Use spaces, not tabs for indents. Guido van Rossum <guido@python.org> parents: 23448 diff changeset	522 if alpha <= 0.0 or beta <= 0.0:
1cc93d501b45 Use spaces, not tabs for indents. Guido van Rossum <guido@python.org> parents: 23448 diff changeset	523 raise ValueError, 'gammavariate: alpha and beta must be > 0.0'
23448 453e59a472b2 Closes patch 529408 deprecating random.stdgamma(). Raymond Hettinger <python@rcn.com> parents: 23443 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 if alpha > 1.0:
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	527
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	528 # 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	529 # 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	530 # Applied Statistics, (1977), 26, No. 1, p71-74
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	531
23443 03dfe7d343db Closes SF bug 527139. Moved temp variables inside guard. Raymond Hettinger <python@rcn.com> parents: 23136 diff changeset	532 ainv = _sqrt(2.0 * alpha - 1.0)
03dfe7d343db Closes SF bug 527139. Moved temp variables inside guard. Raymond Hettinger <python@rcn.com> parents: 23136 diff changeset	533 bbb = alpha - LOG4
03dfe7d343db Closes SF bug 527139. Moved temp variables inside guard. Raymond Hettinger <python@rcn.com> parents: 23136 diff changeset	534 ccc = alpha + ainv
25358 0fbb76b5074b Whitespace normalization and backport: Raymond Hettinger <python@rcn.com> parents: 23450 diff changeset	535
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	536 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	537 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	538 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	539 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	540 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	541 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	542 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	543 if r + SG_MAGICCONST - 4.5*z >= 0.0 or r >= _log(z):
23448 453e59a472b2 Closes patch 529408 deprecating random.stdgamma(). Raymond Hettinger <python@rcn.com> parents: 23443 diff changeset	544 return x * beta
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	545
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	546 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	547 # expovariate(1)
15871 62aeefa01fdd Whitespace normalization. Tim Peters <tim.peters@gmail.com> parents: 14617 diff changeset	548 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	549 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	550 u = random()
23448 453e59a472b2 Closes patch 529408 deprecating random.stdgamma(). Raymond Hettinger <python@rcn.com> parents: 23443 diff changeset	551 return -_log(u) * beta
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	552
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	553 else: # alpha is between 0 and 1 (exclusive)
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	554
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	555 # Uses ALGORITHM GS of Statistical Computing - Kennedy & Gentle
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	556
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	557 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	558 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	559 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	560 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	561 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	562 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	563 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	564 # 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	565 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	566 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	567 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	568 ((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	569 break
23448 453e59a472b2 Closes patch 529408 deprecating random.stdgamma(). Raymond Hettinger <python@rcn.com> parents: 23443 diff changeset	570 return x * beta
453e59a472b2 Closes patch 529408 deprecating random.stdgamma(). Raymond Hettinger <python@rcn.com> parents: 23443 diff changeset	571
453e59a472b2 Closes patch 529408 deprecating random.stdgamma(). Raymond Hettinger <python@rcn.com> parents: 23443 diff changeset	572
453e59a472b2 Closes patch 529408 deprecating random.stdgamma(). Raymond Hettinger <python@rcn.com> parents: 23443 diff changeset	573 def stdgamma(self, alpha, ainv, bbb, ccc):
453e59a472b2 Closes patch 529408 deprecating random.stdgamma(). Raymond Hettinger <python@rcn.com> parents: 23443 diff changeset	574 # This method was (and shall remain) undocumented.
453e59a472b2 Closes patch 529408 deprecating random.stdgamma(). Raymond Hettinger <python@rcn.com> parents: 23443 diff changeset	575 # This method is deprecated
453e59a472b2 Closes patch 529408 deprecating random.stdgamma(). Raymond Hettinger <python@rcn.com> parents: 23443 diff changeset	576 # for the following reasons:
453e59a472b2 Closes patch 529408 deprecating random.stdgamma(). Raymond Hettinger <python@rcn.com> parents: 23443 diff changeset	577 # 1. Returns same as .gammavariate(alpha, 1.0)
453e59a472b2 Closes patch 529408 deprecating random.stdgamma(). Raymond Hettinger <python@rcn.com> parents: 23443 diff changeset	578 # 2. Requires caller to provide 3 extra arguments
453e59a472b2 Closes patch 529408 deprecating random.stdgamma(). Raymond Hettinger <python@rcn.com> parents: 23443 diff changeset	579 # that are functions of alpha anyway
453e59a472b2 Closes patch 529408 deprecating random.stdgamma(). Raymond Hettinger <python@rcn.com> parents: 23443 diff changeset	580 # 3. Can't be used for alpha < 0.5
453e59a472b2 Closes patch 529408 deprecating random.stdgamma(). Raymond Hettinger <python@rcn.com> parents: 23443 diff changeset	581
453e59a472b2 Closes patch 529408 deprecating random.stdgamma(). Raymond Hettinger <python@rcn.com> parents: 23443 diff changeset	582 # ainv = sqrt(2 * alpha - 1)
453e59a472b2 Closes patch 529408 deprecating random.stdgamma(). Raymond Hettinger <python@rcn.com> parents: 23443 diff changeset	583 # bbb = alpha - log(4)
453e59a472b2 Closes patch 529408 deprecating random.stdgamma(). Raymond Hettinger <python@rcn.com> parents: 23443 diff changeset	584 # ccc = alpha + ainv
453e59a472b2 Closes patch 529408 deprecating random.stdgamma(). Raymond Hettinger <python@rcn.com> parents: 23443 diff changeset	585 import warnings
453e59a472b2 Closes patch 529408 deprecating random.stdgamma(). Raymond Hettinger <python@rcn.com> parents: 23443 diff changeset	586 warnings.warn("The stdgamma function is deprecated; "
453e59a472b2 Closes patch 529408 deprecating random.stdgamma(). Raymond Hettinger <python@rcn.com> parents: 23443 diff changeset	587 "use gammavariate() instead",
453e59a472b2 Closes patch 529408 deprecating random.stdgamma(). Raymond Hettinger <python@rcn.com> parents: 23443 diff changeset	588 DeprecationWarning)
453e59a472b2 Closes patch 529408 deprecating random.stdgamma(). Raymond Hettinger <python@rcn.com> parents: 23443 diff changeset	589 return self.gammavariate(alpha, 1.0)
453e59a472b2 Closes patch 529408 deprecating random.stdgamma(). Raymond Hettinger <python@rcn.com> parents: 23443 diff changeset	590
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	591
1576 695fb494a3a2 Added gauss() (same as normal but twice as fast) and betavariate(); Guido van Rossum <guido@python.org> parents: 1575 diff changeset	592
16265 d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	593 ## -------------------- 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	594
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 def gauss(self, mu, sigma):
25581 276b6c452999 Backport 1.33 (omitting the deprecation warning but keeping the deprecation Raymond Hettinger <python@rcn.com> parents: 25359 diff changeset	596 """Gaussian distribution.
276b6c452999 Backport 1.33 (omitting the deprecation warning but keeping the deprecation Raymond Hettinger <python@rcn.com> parents: 25359 diff changeset	597
276b6c452999 Backport 1.33 (omitting the deprecation warning but keeping the deprecation Raymond Hettinger <python@rcn.com> parents: 25359 diff changeset	598 mu is the mean, and sigma is the standard deviation. This is
276b6c452999 Backport 1.33 (omitting the deprecation warning but keeping the deprecation Raymond Hettinger <python@rcn.com> parents: 25359 diff changeset	599 slightly faster than the normalvariate() function.
276b6c452999 Backport 1.33 (omitting the deprecation warning but keeping the deprecation Raymond Hettinger <python@rcn.com> parents: 25359 diff changeset	600
276b6c452999 Backport 1.33 (omitting the deprecation warning but keeping the deprecation Raymond Hettinger <python@rcn.com> parents: 25359 diff changeset	601 Not thread-safe without a lock around calls.
276b6c452999 Backport 1.33 (omitting the deprecation warning but keeping the deprecation Raymond Hettinger <python@rcn.com> parents: 25359 diff changeset	602
276b6c452999 Backport 1.33 (omitting the deprecation warning but keeping the deprecation Raymond Hettinger <python@rcn.com> parents: 25359 diff changeset	603 """
1577 444e349f962f Use float constants directly; cosmetic changes; initialize largest Guido van Rossum <guido@python.org> parents: 1576 diff changeset	604
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	605 # 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	606 # 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	607 #
3c5f09422b69 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 # 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	609 # 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	610 #
3c5f09422b69 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 # 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	612 # (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	613 # (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	614 # (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	615
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	616 # 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	617 # 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	618 # 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	619 # 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	620 # 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	621 # lock here.)
1577 444e349f962f Use float constants directly; cosmetic changes; initialize largest Guido van Rossum <guido@python.org> parents: 1576 diff changeset	622
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	623 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	624 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	625 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	626 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	627 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	628 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	629 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	630 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	631
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	632 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	633
16265 d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	634 ## -------------------- beta --------------------
16271 7ef2382f6123 SF bug 130030: Claim of bad betavariate algorithm. Tim Peters <tim.peters@gmail.com> parents: 16265 diff changeset	635 ## See
7ef2382f6123 SF bug 130030: Claim of bad betavariate algorithm. Tim Peters <tim.peters@gmail.com> parents: 16265 diff changeset	636 ## 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	637 ## 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	638 ##
7ef2382f6123 SF bug 130030: Claim of bad betavariate algorithm. Tim Peters <tim.peters@gmail.com> parents: 16265 diff changeset	639 ## def betavariate(self, alpha, beta):
7ef2382f6123 SF bug 130030: Claim of bad betavariate algorithm. Tim Peters <tim.peters@gmail.com> parents: 16265 diff changeset	640 ## # 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	641 ##
7ef2382f6123 SF bug 130030: Claim of bad betavariate algorithm. Tim Peters <tim.peters@gmail.com> parents: 16265 diff changeset	642 ## y = self.expovariate(alpha)
7ef2382f6123 SF bug 130030: Claim of bad betavariate algorithm. Tim Peters <tim.peters@gmail.com> parents: 16265 diff changeset	643 ## 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	644 ## return z/(y+z)
7ef2382f6123 SF bug 130030: Claim of bad betavariate algorithm. Tim Peters <tim.peters@gmail.com> parents: 16265 diff changeset	645 ##
7ef2382f6123 SF bug 130030: Claim of bad betavariate algorithm. Tim Peters <tim.peters@gmail.com> parents: 16265 diff changeset	646 ## 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	647
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	648 def betavariate(self, alpha, beta):
25581 276b6c452999 Backport 1.33 (omitting the deprecation warning but keeping the deprecation Raymond Hettinger <python@rcn.com> parents: 25359 diff changeset	649 """Beta distribution.
276b6c452999 Backport 1.33 (omitting the deprecation warning but keeping the deprecation Raymond Hettinger <python@rcn.com> parents: 25359 diff changeset	650
276b6c452999 Backport 1.33 (omitting the deprecation warning but keeping the deprecation Raymond Hettinger <python@rcn.com> parents: 25359 diff changeset	651 Conditions on the parameters are alpha > -1 and beta} > -1.
276b6c452999 Backport 1.33 (omitting the deprecation warning but keeping the deprecation Raymond Hettinger <python@rcn.com> parents: 25359 diff changeset	652 Returned values range between 0 and 1.
276b6c452999 Backport 1.33 (omitting the deprecation warning but keeping the deprecation Raymond Hettinger <python@rcn.com> parents: 25359 diff changeset	653
276b6c452999 Backport 1.33 (omitting the deprecation warning but keeping the deprecation Raymond Hettinger <python@rcn.com> parents: 25359 diff changeset	654 """
276b6c452999 Backport 1.33 (omitting the deprecation warning but keeping the deprecation Raymond Hettinger <python@rcn.com> parents: 25359 diff changeset	655
16271 7ef2382f6123 SF bug 130030: Claim of bad betavariate algorithm. Tim Peters <tim.peters@gmail.com> parents: 16265 diff changeset	656 # 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	657 # 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	658 y = self.gammavariate(alpha, 1.)
7ef2382f6123 SF bug 130030: Claim of bad betavariate algorithm. Tim Peters <tim.peters@gmail.com> parents: 16265 diff changeset	659 if y == 0:
7ef2382f6123 SF bug 130030: Claim of bad betavariate algorithm. Tim Peters <tim.peters@gmail.com> parents: 16265 diff changeset	660 return 0.0
7ef2382f6123 SF bug 130030: Claim of bad betavariate algorithm. Tim Peters <tim.peters@gmail.com> parents: 16265 diff changeset	661 else:
7ef2382f6123 SF bug 130030: Claim of bad betavariate algorithm. Tim Peters <tim.peters@gmail.com> parents: 16265 diff changeset	662 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	663
16265 d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	664 ## -------------------- Pareto --------------------
6698 b73eb4e6face Added Pareto and Weibull distributions, courtesy Jeremy Hylton. Guido van Rossum <guido@python.org> parents: 1618 diff changeset	665
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	666 def paretovariate(self, alpha):
25581 276b6c452999 Backport 1.33 (omitting the deprecation warning but keeping the deprecation Raymond Hettinger <python@rcn.com> parents: 25359 diff changeset	667 """Pareto distribution. alpha is the shape parameter."""
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	668 # Jain, pg. 495
6698 b73eb4e6face Added Pareto and Weibull distributions, courtesy Jeremy Hylton. Guido van Rossum <guido@python.org> parents: 1618 diff changeset	669
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	670 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	671 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	672
16265 d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	673 ## -------------------- Weibull --------------------
6698 b73eb4e6face Added Pareto and Weibull distributions, courtesy Jeremy Hylton. Guido van Rossum <guido@python.org> parents: 1618 diff changeset	674
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	675 def weibullvariate(self, alpha, beta):
25581 276b6c452999 Backport 1.33 (omitting the deprecation warning but keeping the deprecation Raymond Hettinger <python@rcn.com> parents: 25359 diff changeset	676 """Weibull distribution.
276b6c452999 Backport 1.33 (omitting the deprecation warning but keeping the deprecation Raymond Hettinger <python@rcn.com> parents: 25359 diff changeset	677
276b6c452999 Backport 1.33 (omitting the deprecation warning but keeping the deprecation Raymond Hettinger <python@rcn.com> parents: 25359 diff changeset	678 alpha is the scale parameter and beta is the shape parameter.
276b6c452999 Backport 1.33 (omitting the deprecation warning but keeping the deprecation Raymond Hettinger <python@rcn.com> parents: 25359 diff changeset	679
276b6c452999 Backport 1.33 (omitting the deprecation warning but keeping the deprecation Raymond Hettinger <python@rcn.com> parents: 25359 diff changeset	680 """
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	681 # 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	682
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	683 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	684 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	685
16265 d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	686 ## -------------------- test program --------------------
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	687
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	688 def _test_generator(n, funccall):
15871 62aeefa01fdd Whitespace normalization. Tim Peters <tim.peters@gmail.com> parents: 14617 diff changeset	689 import time
62aeefa01fdd Whitespace normalization. Tim Peters <tim.peters@gmail.com> parents: 14617 diff changeset	690 print n, 'times', funccall
62aeefa01fdd Whitespace normalization. Tim Peters <tim.peters@gmail.com> parents: 14617 diff changeset	691 code = compile(funccall, funccall, 'eval')
62aeefa01fdd Whitespace normalization. Tim Peters <tim.peters@gmail.com> parents: 14617 diff changeset	692 sum = 0.0
62aeefa01fdd Whitespace normalization. Tim Peters <tim.peters@gmail.com> parents: 14617 diff changeset	693 sqsum = 0.0
62aeefa01fdd Whitespace normalization. Tim Peters <tim.peters@gmail.com> parents: 14617 diff changeset	694 smallest = 1e10
62aeefa01fdd Whitespace normalization. Tim Peters <tim.peters@gmail.com> parents: 14617 diff changeset	695 largest = -1e10
62aeefa01fdd Whitespace normalization. Tim Peters <tim.peters@gmail.com> parents: 14617 diff changeset	696 t0 = time.time()
62aeefa01fdd Whitespace normalization. Tim Peters <tim.peters@gmail.com> parents: 14617 diff changeset	697 for i in range(n):
62aeefa01fdd Whitespace normalization. Tim Peters <tim.peters@gmail.com> parents: 14617 diff changeset	698 x = eval(code)
62aeefa01fdd Whitespace normalization. Tim Peters <tim.peters@gmail.com> parents: 14617 diff changeset	699 sum = sum + x
62aeefa01fdd Whitespace normalization. Tim Peters <tim.peters@gmail.com> parents: 14617 diff changeset	700 sqsum = sqsum + x*x
62aeefa01fdd Whitespace normalization. Tim Peters <tim.peters@gmail.com> parents: 14617 diff changeset	701 smallest = min(x, smallest)
62aeefa01fdd Whitespace normalization. Tim Peters <tim.peters@gmail.com> parents: 14617 diff changeset	702 largest = max(x, largest)
62aeefa01fdd Whitespace normalization. Tim Peters <tim.peters@gmail.com> parents: 14617 diff changeset	703 t1 = time.time()
62aeefa01fdd Whitespace normalization. Tim Peters <tim.peters@gmail.com> parents: 14617 diff changeset	704 print round(t1-t0, 3), 'sec,',
62aeefa01fdd Whitespace normalization. Tim Peters <tim.peters@gmail.com> parents: 14617 diff changeset	705 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	706 stddev = _sqrt(sqsum/n - avg*avg)
15871 62aeefa01fdd Whitespace normalization. Tim Peters <tim.peters@gmail.com> parents: 14617 diff changeset	707 print 'avg %g, stddev %g, min %g, max %g' % \
62aeefa01fdd Whitespace normalization. Tim Peters <tim.peters@gmail.com> parents: 14617 diff changeset	708 (avg, stddev, smallest, largest)
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	709
23448 453e59a472b2 Closes patch 529408 deprecating random.stdgamma(). Raymond Hettinger <python@rcn.com> parents: 23443 diff changeset	710 def _test(N=20000):
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	711 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	712 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	713 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	714 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	715 _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	716 _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	717 _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	718 _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	719 _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	720 _test_generator(N, 'vonmisesvariate(0.0, 1.0)')
23448 453e59a472b2 Closes patch 529408 deprecating random.stdgamma(). Raymond Hettinger <python@rcn.com> parents: 23443 diff changeset	721 _test_generator(N, 'gammavariate(0.01, 1.0)')
453e59a472b2 Closes patch 529408 deprecating random.stdgamma(). Raymond Hettinger <python@rcn.com> parents: 23443 diff changeset	722 _test_generator(N, 'gammavariate(0.1, 1.0)')
25358 0fbb76b5074b Whitespace normalization and backport: Raymond Hettinger <python@rcn.com> parents: 23450 diff changeset	723 _test_generator(N, 'gammavariate(0.1, 2.0)')
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	724 _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	725 _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	726 _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	727 _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	728 _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	729 _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	730 _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	731 _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	732 _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	733 _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	734
16265 d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	735 # Test jumpahead.
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	736 s = getstate()
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	737 jumpahead(N)
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	738 r1 = random()
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	739 # 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	740 setstate(s)
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	741 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	742 random()
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	743 r2 = random()
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	744 if r1 != r2:
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	745 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	746
16292 0501c2a10315 New comment block to Clarify a subtlety. Tim Peters <tim.peters@gmail.com> parents: 16272 diff changeset	747 # 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	748 # 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	749 # 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	750 # 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	751 # 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	752 _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	753 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	754 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	755 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	756 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	757 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	758 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	759 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	760 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	761 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	762 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	763 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	764 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	765 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	766 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	767 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	768 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	769 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	770 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	771 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	772 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	773 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	774 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	775
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	776 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	777 _test()

Mercurial > cpython-lru_cache-weakref

annotate Lib/random.py @ 25838:8540887bcec6 2.2