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

annotate Lib/random.py @ 24042:63fbbed10714 legacy-trunk

Simplify HTTPSConnection constructor. See discussion in SF bug 458463.

author	Jeremy Hylton <jeremy@alum.mit.edu>
date	Fri, 28 Jun 2002 23:38:14 +0000
parents	0a4c92559a0b
children	4e795fe9f54b

rev	line source
11707 6f4146846337 The third and final doc-string sweep by Ka-Ping Yee. Guido van Rossum <guido@python.org> parents: 11200 diff changeset	1 """Random variable generators.
6f4146846337 The third and final doc-string sweep by Ka-Ping Yee. Guido van Rossum <guido@python.org> parents: 11200 diff changeset	2
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	3 integers
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	4 --------
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	5 uniform within range
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	6
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	7 sequences
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	8 ---------
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	9 pick random element
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	10 generate random permutation
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	11
11707 6f4146846337 The third and final doc-string sweep by Ka-Ping Yee. Guido van Rossum <guido@python.org> parents: 11200 diff changeset	12 distributions on the real line:
6f4146846337 The third and final doc-string sweep by Ka-Ping Yee. Guido van Rossum <guido@python.org> parents: 11200 diff changeset	13 ------------------------------
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	14 uniform
11707 6f4146846337 The third and final doc-string sweep by Ka-Ping Yee. Guido van Rossum <guido@python.org> parents: 11200 diff changeset	15 normal (Gaussian)
6f4146846337 The third and final doc-string sweep by Ka-Ping Yee. Guido van Rossum <guido@python.org> parents: 11200 diff changeset	16 lognormal
6f4146846337 The third and final doc-string sweep by Ka-Ping Yee. Guido van Rossum <guido@python.org> parents: 11200 diff changeset	17 negative exponential
6f4146846337 The third and final doc-string sweep by Ka-Ping Yee. Guido van Rossum <guido@python.org> parents: 11200 diff changeset	18 gamma
6f4146846337 The third and final doc-string sweep by Ka-Ping Yee. Guido van Rossum <guido@python.org> parents: 11200 diff changeset	19 beta
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	20
11707 6f4146846337 The third and final doc-string sweep by Ka-Ping Yee. Guido van Rossum <guido@python.org> parents: 11200 diff changeset	21 distributions on the circle (angles 0 to 2pi)
6f4146846337 The third and final doc-string sweep by Ka-Ping Yee. Guido van Rossum <guido@python.org> parents: 11200 diff changeset	22 ---------------------------------------------
6f4146846337 The third and final doc-string sweep by Ka-Ping Yee. Guido van Rossum <guido@python.org> parents: 11200 diff changeset	23 circular uniform
6f4146846337 The third and final doc-string sweep by Ka-Ping Yee. Guido van Rossum <guido@python.org> parents: 11200 diff changeset	24 von Mises
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	25
11707 6f4146846337 The third and final doc-string sweep by Ka-Ping Yee. Guido van Rossum <guido@python.org> parents: 11200 diff changeset	26 Translated from anonymously contributed C/C++ source.
6f4146846337 The third and final doc-string sweep by Ka-Ping Yee. Guido van Rossum <guido@python.org> parents: 11200 diff changeset	27
16272 835e9dd54bfb The combo of getstate/setstate/jumpahead is very powerful, but needs Tim Peters <tim.peters@gmail.com> parents: 16271 diff changeset	28 Multi-threading note: the random number generator used here is not thread-
835e9dd54bfb The combo of getstate/setstate/jumpahead is very powerful, but needs Tim Peters <tim.peters@gmail.com> parents: 16271 diff changeset	29 safe; it is possible that two calls return the same random value. However,
835e9dd54bfb The combo of getstate/setstate/jumpahead is very powerful, but needs Tim Peters <tim.peters@gmail.com> parents: 16271 diff changeset	30 you can instantiate a different instance of Random() in each thread to get
835e9dd54bfb The combo of getstate/setstate/jumpahead is very powerful, but needs Tim Peters <tim.peters@gmail.com> parents: 16271 diff changeset	31 generators that don't share state, then use .setstate() and .jumpahead() to
835e9dd54bfb The combo of getstate/setstate/jumpahead is very powerful, but needs Tim Peters <tim.peters@gmail.com> parents: 16271 diff changeset	32 move the generators to disjoint segments of the full period. For example,
835e9dd54bfb The combo of getstate/setstate/jumpahead is very powerful, but needs Tim Peters <tim.peters@gmail.com> parents: 16271 diff changeset	33
835e9dd54bfb The combo of getstate/setstate/jumpahead is very powerful, but needs Tim Peters <tim.peters@gmail.com> parents: 16271 diff changeset	34 def create_generators(num, delta, firstseed=None):
835e9dd54bfb The combo of getstate/setstate/jumpahead is very powerful, but needs Tim Peters <tim.peters@gmail.com> parents: 16271 diff changeset	35 ""\"Return list of num distinct generators.
835e9dd54bfb The combo of getstate/setstate/jumpahead is very powerful, but needs Tim Peters <tim.peters@gmail.com> parents: 16271 diff changeset	36 Each generator has its own unique segment of delta elements from
835e9dd54bfb The combo of getstate/setstate/jumpahead is very powerful, but needs Tim Peters <tim.peters@gmail.com> parents: 16271 diff changeset	37 Random.random()'s full period.
835e9dd54bfb The combo of getstate/setstate/jumpahead is very powerful, but needs Tim Peters <tim.peters@gmail.com> parents: 16271 diff changeset	38 Seed the first generator with optional arg firstseed (default is
835e9dd54bfb The combo of getstate/setstate/jumpahead is very powerful, but needs Tim Peters <tim.peters@gmail.com> parents: 16271 diff changeset	39 None, to seed from current time).
835e9dd54bfb The combo of getstate/setstate/jumpahead is very powerful, but needs Tim Peters <tim.peters@gmail.com> parents: 16271 diff changeset	40 ""\"
835e9dd54bfb The combo of getstate/setstate/jumpahead is very powerful, but needs Tim Peters <tim.peters@gmail.com> parents: 16271 diff changeset	41
835e9dd54bfb The combo of getstate/setstate/jumpahead is very powerful, but needs Tim Peters <tim.peters@gmail.com> parents: 16271 diff changeset	42 from random import Random
835e9dd54bfb The combo of getstate/setstate/jumpahead is very powerful, but needs Tim Peters <tim.peters@gmail.com> parents: 16271 diff changeset	43 g = Random(firstseed)
835e9dd54bfb The combo of getstate/setstate/jumpahead is very powerful, but needs Tim Peters <tim.peters@gmail.com> parents: 16271 diff changeset	44 result = [g]
835e9dd54bfb The combo of getstate/setstate/jumpahead is very powerful, but needs Tim Peters <tim.peters@gmail.com> parents: 16271 diff changeset	45 for i in range(num - 1):
835e9dd54bfb The combo of getstate/setstate/jumpahead is very powerful, but needs Tim Peters <tim.peters@gmail.com> parents: 16271 diff changeset	46 laststate = g.getstate()
835e9dd54bfb The combo of getstate/setstate/jumpahead is very powerful, but needs Tim Peters <tim.peters@gmail.com> parents: 16271 diff changeset	47 g = Random()
835e9dd54bfb The combo of getstate/setstate/jumpahead is very powerful, but needs Tim Peters <tim.peters@gmail.com> parents: 16271 diff changeset	48 g.setstate(laststate)
835e9dd54bfb The combo of getstate/setstate/jumpahead is very powerful, but needs Tim Peters <tim.peters@gmail.com> parents: 16271 diff changeset	49 g.jumpahead(delta)
835e9dd54bfb The combo of getstate/setstate/jumpahead is very powerful, but needs Tim Peters <tim.peters@gmail.com> parents: 16271 diff changeset	50 result.append(g)
835e9dd54bfb The combo of getstate/setstate/jumpahead is very powerful, but needs Tim Peters <tim.peters@gmail.com> parents: 16271 diff changeset	51 return result
835e9dd54bfb The combo of getstate/setstate/jumpahead is very powerful, but needs Tim Peters <tim.peters@gmail.com> parents: 16271 diff changeset	52
835e9dd54bfb The combo of getstate/setstate/jumpahead is very powerful, but needs Tim Peters <tim.peters@gmail.com> parents: 16271 diff changeset	53 gens = create_generators(10, 1000000)
835e9dd54bfb The combo of getstate/setstate/jumpahead is very powerful, but needs Tim Peters <tim.peters@gmail.com> parents: 16271 diff changeset	54
835e9dd54bfb The combo of getstate/setstate/jumpahead is very powerful, but needs Tim Peters <tim.peters@gmail.com> parents: 16271 diff changeset	55 That creates 10 distinct generators, which can be passed out to 10 distinct
835e9dd54bfb The combo of getstate/setstate/jumpahead is very powerful, but needs Tim Peters <tim.peters@gmail.com> parents: 16271 diff changeset	56 threads. The generators don't share state so can be called safely in
835e9dd54bfb The combo of getstate/setstate/jumpahead is very powerful, but needs Tim Peters <tim.peters@gmail.com> parents: 16271 diff changeset	57 parallel. So long as no thread calls its g.random() more than a million
835e9dd54bfb The combo of getstate/setstate/jumpahead is very powerful, but needs Tim Peters <tim.peters@gmail.com> parents: 16271 diff changeset	58 times (the second argument to create_generators), the sequences seen by
835e9dd54bfb The combo of getstate/setstate/jumpahead is very powerful, but needs Tim Peters <tim.peters@gmail.com> parents: 16271 diff changeset	59 each thread will not overlap.
835e9dd54bfb The combo of getstate/setstate/jumpahead is very powerful, but needs Tim Peters <tim.peters@gmail.com> parents: 16271 diff changeset	60
835e9dd54bfb The combo of getstate/setstate/jumpahead is very powerful, but needs Tim Peters <tim.peters@gmail.com> parents: 16271 diff changeset	61 The period of the underlying Wichmann-Hill generator is 6,953,607,871,644,
835e9dd54bfb The combo of getstate/setstate/jumpahead is very powerful, but needs Tim Peters <tim.peters@gmail.com> parents: 16271 diff changeset	62 and that limits how far this technique can be pushed.
835e9dd54bfb The combo of getstate/setstate/jumpahead is very powerful, but needs Tim Peters <tim.peters@gmail.com> parents: 16271 diff changeset	63
835e9dd54bfb The combo of getstate/setstate/jumpahead is very powerful, but needs Tim Peters <tim.peters@gmail.com> parents: 16271 diff changeset	64 Just for fun, note that since we know the period, .jumpahead() can also be
835e9dd54bfb The combo of getstate/setstate/jumpahead is very powerful, but needs Tim Peters <tim.peters@gmail.com> parents: 16271 diff changeset	65 used to "move backward in time":
835e9dd54bfb The combo of getstate/setstate/jumpahead is very powerful, but needs Tim Peters <tim.peters@gmail.com> parents: 16271 diff changeset	66
835e9dd54bfb The combo of getstate/setstate/jumpahead is very powerful, but needs Tim Peters <tim.peters@gmail.com> parents: 16271 diff changeset	67 >>> g = Random(42) # arbitrary
835e9dd54bfb The combo of getstate/setstate/jumpahead is very powerful, but needs Tim Peters <tim.peters@gmail.com> parents: 16271 diff changeset	68 >>> g.random()
16379 5f0683a69efc Change random.seed() so that it can get at the full range of possible Tim Peters <tim.peters@gmail.com> parents: 16292 diff changeset	69 0.25420336316883324
16272 835e9dd54bfb The combo of getstate/setstate/jumpahead is very powerful, but needs Tim Peters <tim.peters@gmail.com> parents: 16271 diff changeset	70 >>> g.jumpahead(6953607871644L - 1) # move back one
835e9dd54bfb The combo of getstate/setstate/jumpahead is very powerful, but needs Tim Peters <tim.peters@gmail.com> parents: 16271 diff changeset	71 >>> g.random()
16379 5f0683a69efc Change random.seed() so that it can get at the full range of possible Tim Peters <tim.peters@gmail.com> parents: 16292 diff changeset	72 0.25420336316883324
11707 6f4146846337 The third and final doc-string sweep by Ka-Ping Yee. Guido van Rossum <guido@python.org> parents: 11200 diff changeset	73 """
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	74 # XXX The docstring sucks.
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	75
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	76 from math import log as _log, exp as _exp, pi as _pi, e as _e
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	77 from math import sqrt as _sqrt, acos as _acos, cos as _cos, sin as _sin
8455 af9273b1073a Make gauss() semi-thread-safe. It can still give duplicate results, Guido van Rossum <guido@python.org> parents: 8393 diff changeset	78
16613 f68dbffff927 bunch more __all__ lists Skip Montanaro <skip@pobox.com> parents: 16386 diff changeset	79 __all__ = ["Random","seed","random","uniform","randint","choice",
f68dbffff927 bunch more __all__ lists Skip Montanaro <skip@pobox.com> parents: 16386 diff changeset	80 "randrange","shuffle","normalvariate","lognormvariate",
f68dbffff927 bunch more __all__ lists Skip Montanaro <skip@pobox.com> parents: 16386 diff changeset	81 "cunifvariate","expovariate","vonmisesvariate","gammavariate",
f68dbffff927 bunch more __all__ lists Skip Montanaro <skip@pobox.com> parents: 16386 diff changeset	82 "stdgamma","gauss","betavariate","paretovariate","weibullvariate",
f68dbffff927 bunch more __all__ lists Skip Montanaro <skip@pobox.com> parents: 16386 diff changeset	83 "getstate","setstate","jumpahead","whseed"]
16616 e2a63584566f Whitespace normalization. Tim Peters <tim.peters@gmail.com> parents: 16613 diff changeset	84
21049 fed5071da957 SF patch 483059: Avoid use of eval() in random.py, from Finn Bock. Tim Peters <tim.peters@gmail.com> parents: 16616 diff changeset	85 def _verify(name, computed, expected):
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	86 if abs(computed - expected) > 1e-7:
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	87 raise ValueError(
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	88 "computed value for %s deviates too much "
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	89 "(computed %g, expected %g)" % (name, computed, expected))
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	90
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	91 NV_MAGICCONST = 4 * _exp(-0.5)/_sqrt(2.0)
21049 fed5071da957 SF patch 483059: Avoid use of eval() in random.py, from Finn Bock. Tim Peters <tim.peters@gmail.com> parents: 16616 diff changeset	92 _verify('NV_MAGICCONST', NV_MAGICCONST, 1.71552776992141)
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	93
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	94 TWOPI = 2.0*_pi
21049 fed5071da957 SF patch 483059: Avoid use of eval() in random.py, from Finn Bock. Tim Peters <tim.peters@gmail.com> parents: 16616 diff changeset	95 _verify('TWOPI', TWOPI, 6.28318530718)
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	96
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	97 LOG4 = _log(4.0)
21049 fed5071da957 SF patch 483059: Avoid use of eval() in random.py, from Finn Bock. Tim Peters <tim.peters@gmail.com> parents: 16616 diff changeset	98 _verify('LOG4', LOG4, 1.38629436111989)
8393 7669ddf0e7d4 Add Interfaces to replace remaining needs for importing whrandom. Guido van Rossum <guido@python.org> parents: 7881 diff changeset	99
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	100 SG_MAGICCONST = 1.0 + _log(4.5)
21049 fed5071da957 SF patch 483059: Avoid use of eval() in random.py, from Finn Bock. Tim Peters <tim.peters@gmail.com> parents: 16616 diff changeset	101 _verify('SG_MAGICCONST', SG_MAGICCONST, 2.50407739677627)
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	102
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	103 del _verify
8393 7669ddf0e7d4 Add Interfaces to replace remaining needs for importing whrandom. Guido van Rossum <guido@python.org> parents: 7881 diff changeset	104
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	105 # Translated by Guido van Rossum from C source provided by
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	106 # Adrian Baddeley.
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	107
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	108 class Random:
23531 a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	109 """Random number generator base class used by bound module functions.
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	110
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	111 Used to instantiate instances of Random to get generators that don't
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	112 share state. Especially useful for multi-threaded programs, creating
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	113 a different instance of Random for each thread, and using the jumpahead()
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	114 method to ensure that the generated sequences seen by each thread don't
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	115 overlap.
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	116
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	117 Class Random can also be subclassed if you want to use a different basic
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	118 generator of your own devising: in that case, override the following
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	119 methods: random(), seed(), getstate(), setstate() and jumpahead().
23536 0a4c92559a0b Whitespace normalized. Raymond Hettinger <python@rcn.com> parents: 23531 diff changeset	120
23531 a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	121 """
8393 7669ddf0e7d4 Add Interfaces to replace remaining needs for importing whrandom. Guido van Rossum <guido@python.org> parents: 7881 diff changeset	122
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	123 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	124
3c5f09422b69 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 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	126 """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	127
3c5f09422b69 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 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	129 """
3c5f09422b69 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 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	132
16265 d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	133 ## -------------------- core generator -------------------
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	134
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	135 # 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	136 # 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	137 # 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	138
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	139 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	140 """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	141
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 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	143
16386 c2555b4f38a3 Repaired a docstring. Tim Peters <tim.peters@gmail.com> parents: 16379 diff changeset	144 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	145
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 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	147 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	148 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	149 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	150 """
8393 7669ddf0e7d4 Add Interfaces to replace remaining needs for importing whrandom. Guido van Rossum <guido@python.org> parents: 7881 diff changeset	151
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	152 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	153 # 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	154 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	155 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	156
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 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	158 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	159
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 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	161 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	162 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	163 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	164
23380 9be01b7b6c80 random.gauss() uses a piece of hidden state used by nothing else, Tim Peters <tim.peters@gmail.com> parents: 23023 diff changeset	165 self.gauss_next = None
9be01b7b6c80 random.gauss() uses a piece of hidden state used by nothing else, Tim Peters <tim.peters@gmail.com> parents: 23023 diff changeset	166
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	167 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	168 """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	169
3c5f09422b69 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 # 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	171 #
3c5f09422b69 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 # 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	173 # 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	174 # 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	175 # 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	176 #
3c5f09422b69 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 # 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	178 # 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	179 # 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	180 #
3c5f09422b69 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 # 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	182 # 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	183 # 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	184
3c5f09422b69 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 # 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	186 # 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	187 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	188 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	189 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	190 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	191 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	192 # 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	193
3c5f09422b69 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 # 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	195 # 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	196 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	197
16265 d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	198 def getstate(self):
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	199 """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	200 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	201
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	202 def setstate(self, state):
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	203 """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	204 version = state[0]
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	205 if version == 1:
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	206 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	207 else:
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	208 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	209 "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	210 (version, self.VERSION))
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	211
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	212 def jumpahead(self, n):
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	213 """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	214
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	215 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	216
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	217 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	218 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	219 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	220 r2.setstate(r1.getstate())
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	221 r2.jumpahead(1000000)
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	222 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	223 period.
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	224 """
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 if not n >= 0:
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	227 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	228 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	229 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	230 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	231 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	232 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	233
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	234 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	235 """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	236
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 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	238 """
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 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	241 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	242 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	243 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	244 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	245 # 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	246 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	247 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	248 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	249 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	250 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	251 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	252 # 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	253 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	254
23380 9be01b7b6c80 random.gauss() uses a piece of hidden state used by nothing else, Tim Peters <tim.peters@gmail.com> parents: 23023 diff changeset	255 self.gauss_next = None
9be01b7b6c80 random.gauss() uses a piece of hidden state used by nothing else, Tim Peters <tim.peters@gmail.com> parents: 23023 diff changeset	256
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	257 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	258 """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	259
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 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	261 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	262 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	263
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 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	265 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	266 """
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 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	269 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	270 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	271 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	272 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	273 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	274 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	275 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	276 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	277 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	278 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	279
16265 d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	280 ## ---- 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	281 ## ---- 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	282
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	283 ## -------------------- pickle support -------------------
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	284
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	285 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	286 return self.getstate()
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	287
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	288 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	289 self.setstate(state)
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	290
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	291 ## -------------------- integer methods -------------------
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	292
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	293 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	294 """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	295
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	296 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	297 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	298 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	299 """
3c5f09422b69 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 # This code is a bit messy to make it fast for the
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	302 # common case while still doing adequate error checking
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	303 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	304 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	305 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	306 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	307 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	308 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	309 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	310 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	311 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	312 raise ValueError, "non-integer stop for randrange()"
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	313 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	314 if istart < istop:
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	315 return istart + int(self.random() *
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	316 (istop - istart))
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	317 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	318 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	319 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	320 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	321 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	322 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	323 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	324 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	325 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	326 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	327
3c5f09422b69 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 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	329 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	330 return istart + istepint(self.random() n)
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	331
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	332 def 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	333 """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	334 """
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	335
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	336 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	337
16265 d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	338 ## -------------------- sequence methods -------------------
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	339
16242 3c5f09422b69 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 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	341 """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	342 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	343
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	344 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	345 """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	346
3c5f09422b69 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 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	348 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	349
3c5f09422b69 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 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	351 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	352 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	353 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	354 """
3c5f09422b69 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
3c5f09422b69 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 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	357 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	358 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	359 # 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	360 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	361 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	362
16265 d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	363 ## -------------------- real-valued distributions -------------------
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	364
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	365 ## -------------------- 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	366
3c5f09422b69 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 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	368 """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	369 return a + (b-a) * self.random()
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	370
16265 d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	371 ## -------------------- normal distribution --------------------
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	372
16242 3c5f09422b69 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 def normalvariate(self, mu, sigma):
23531 a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	374 """Normal distribution.
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	375
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	376 mu is the mean, and sigma is the standard deviation.
23536 0a4c92559a0b Whitespace normalized. Raymond Hettinger <python@rcn.com> parents: 23531 diff changeset	377
23531 a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	378 """
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	379 # 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	380
3c5f09422b69 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 # 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	382 # 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	383 # 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	384 # Math Software, 3, (1977), pp257-260.
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	385
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	386 random = self.random
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	387 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	388 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	389 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	390 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	391 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	392 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	393 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	394 return mu + z*sigma
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	395
16265 d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	396 ## -------------------- lognormal distribution --------------------
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	397
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	398 def lognormvariate(self, mu, sigma):
23531 a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	399 """Log normal distribution.
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	400
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	401 If you take the natural logarithm of this distribution, you'll get a
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	402 normal distribution with mean mu and standard deviation sigma.
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	403 mu can have any value, and sigma must be greater than zero.
23536 0a4c92559a0b Whitespace normalized. Raymond Hettinger <python@rcn.com> parents: 23531 diff changeset	404
23531 a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	405 """
16242 3c5f09422b69 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 return _exp(self.normalvariate(mu, sigma))
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	407
16265 d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	408 ## -------------------- circular uniform --------------------
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	409
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	410 def cunifvariate(self, mean, arc):
23531 a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	411 """Circular uniform distribution.
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	412
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	413 mean is the mean angle, and arc is the range of the distribution,
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	414 centered around the mean angle. Both values must be expressed in
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	415 radians. Returned values range between mean - arc/2 and
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	416 mean + arc/2 and are normalized to between 0 and pi.
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	417
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	418 Deprecated in version 2.3. Use:
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	419 (mean + arc * (Random.random() - 0.5)) % Math.pi
23536 0a4c92559a0b Whitespace normalized. Raymond Hettinger <python@rcn.com> parents: 23531 diff changeset	420
23531 a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	421 """
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	422 # 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	423 # arc: range of distribution (in radians between 0 and pi)
23531 a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	424 import warnings
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	425 warnings.warn("The cunifvariate function is deprecated; Use (mean "
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	426 "+ arc * (Random.random() - 0.5)) % Math.pi instead",
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	427 DeprecationWarning)
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	428
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	429 return (mean + arc * (self.random() - 0.5)) % _pi
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	430
16265 d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	431 ## -------------------- exponential distribution --------------------
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	432
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	433 def expovariate(self, lambd):
23531 a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	434 """Exponential distribution.
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	435
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	436 lambd is 1.0 divided by the desired mean. (The parameter would be
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	437 called "lambda", but that is a reserved word in Python.) Returned
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	438 values range from 0 to positive infinity.
23536 0a4c92559a0b Whitespace normalized. Raymond Hettinger <python@rcn.com> parents: 23531 diff changeset	439
23531 a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	440 """
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	441 # 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	442 # ('lambda' is a Python reserved word)
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	443
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	444 random = self.random
15871 62aeefa01fdd Whitespace normalization. Tim Peters <tim.peters@gmail.com> parents: 14617 diff changeset	445 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	446 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	447 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	448 return -_log(u)/lambd
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	449
16265 d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	450 ## -------------------- von Mises distribution --------------------
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	451
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	452 def vonmisesvariate(self, mu, kappa):
23531 a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	453 """Circular data distribution.
23536 0a4c92559a0b Whitespace normalized. Raymond Hettinger <python@rcn.com> parents: 23531 diff changeset	454
23531 a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	455 mu is the mean angle, expressed in radians between 0 and 2*pi, and
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	456 kappa is the concentration parameter, which must be greater than or
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	457 equal to zero. If kappa is equal to zero, this distribution reduces
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	458 to a uniform random angle over the range 0 to 2*pi.
23536 0a4c92559a0b Whitespace normalized. Raymond Hettinger <python@rcn.com> parents: 23531 diff changeset	459
23531 a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 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 # 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	462 # 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	463 # if kappa = 0 generate uniform random angle
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	464
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	465 # 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	466 # "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	467 # 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	468
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	469 # 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	470 # 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	471
16242 3c5f09422b69 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 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	473 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	474 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	475
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	476 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	477 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	478 r = (1.0 + b * b)/(2.0 * b)
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	479
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	480 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	481 u1 = random()
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	482
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	483 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	484 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	485 c = kappa * (r - f)
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	486
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	487 u2 = random()
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 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	490 break
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 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	493 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	494 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	495 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	496 theta = (mu % TWOPI) - _acos(f)
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 return theta
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	499
16265 d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	500 ## -------------------- gamma distribution --------------------
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	501
16242 3c5f09422b69 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 def gammavariate(self, alpha, beta):
23531 a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	503 """Gamma distribution. Not the gamma function!
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	504
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	505 Conditions on the parameters are alpha > 0 and beta > 0.
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	506
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	507 """
23521 a90faa5f9417 Whitespace normalization. Tim Peters <tim.peters@gmail.com> parents: 23451 diff changeset	508
23447 08ccb0f3e2d4 Closes patch 529408 deprecating random.stdgamma(). Raymond Hettinger <python@rcn.com> parents: 23442 diff changeset	509 # alpha > 0, beta > 0, mean is alphabeta, variance is alphabeta**2
23521 a90faa5f9417 Whitespace normalization. Tim Peters <tim.peters@gmail.com> parents: 23451 diff changeset	510
23451 273dd2508c57 Use spaces, not tabs for indents. Guido van Rossum <guido@python.org> parents: 23447 diff changeset	511 # Warning: a few older sources define the gamma distribution in terms
273dd2508c57 Use spaces, not tabs for indents. Guido van Rossum <guido@python.org> parents: 23447 diff changeset	512 # of alpha > -1.0
273dd2508c57 Use spaces, not tabs for indents. Guido van Rossum <guido@python.org> parents: 23447 diff changeset	513 if alpha <= 0.0 or beta <= 0.0:
273dd2508c57 Use spaces, not tabs for indents. Guido van Rossum <guido@python.org> parents: 23447 diff changeset	514 raise ValueError, 'gammavariate: alpha and beta must be > 0.0'
23521 a90faa5f9417 Whitespace normalization. Tim Peters <tim.peters@gmail.com> parents: 23451 diff changeset	515
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	516 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	517 if alpha > 1.0:
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	518
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	519 # 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	520 # 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	521 # Applied Statistics, (1977), 26, No. 1, p71-74
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	522
23442 b15896053933 Closes SF bug 527139. Moved temp variables inside guard. Raymond Hettinger <python@rcn.com> parents: 23380 diff changeset	523 ainv = _sqrt(2.0 * alpha - 1.0)
b15896053933 Closes SF bug 527139. Moved temp variables inside guard. Raymond Hettinger <python@rcn.com> parents: 23380 diff changeset	524 bbb = alpha - LOG4
b15896053933 Closes SF bug 527139. Moved temp variables inside guard. Raymond Hettinger <python@rcn.com> parents: 23380 diff changeset	525 ccc = alpha + ainv
23521 a90faa5f9417 Whitespace normalization. Tim Peters <tim.peters@gmail.com> parents: 23451 diff changeset	526
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	527 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	528 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	529 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	530 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	531 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	532 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	533 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	534 if r + SG_MAGICCONST - 4.5*z >= 0.0 or r >= _log(z):
23447 08ccb0f3e2d4 Closes patch 529408 deprecating random.stdgamma(). Raymond Hettinger <python@rcn.com> parents: 23442 diff changeset	535 return x * beta
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	536
16242 3c5f09422b69 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 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	538 # expovariate(1)
15871 62aeefa01fdd Whitespace normalization. Tim Peters <tim.peters@gmail.com> parents: 14617 diff changeset	539 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	540 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	541 u = random()
23447 08ccb0f3e2d4 Closes patch 529408 deprecating random.stdgamma(). Raymond Hettinger <python@rcn.com> parents: 23442 diff changeset	542 return -_log(u) * beta
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	543
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	544 else: # alpha is between 0 and 1 (exclusive)
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 # Uses ALGORITHM GS of Statistical Computing - Kennedy & Gentle
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	547
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	548 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	549 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	550 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	551 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	552 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	553 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	554 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	555 # 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	556 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	557 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	558 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	559 ((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	560 break
23447 08ccb0f3e2d4 Closes patch 529408 deprecating random.stdgamma(). Raymond Hettinger <python@rcn.com> parents: 23442 diff changeset	561 return x * beta
08ccb0f3e2d4 Closes patch 529408 deprecating random.stdgamma(). Raymond Hettinger <python@rcn.com> parents: 23442 diff changeset	562
08ccb0f3e2d4 Closes patch 529408 deprecating random.stdgamma(). Raymond Hettinger <python@rcn.com> parents: 23442 diff changeset	563
08ccb0f3e2d4 Closes patch 529408 deprecating random.stdgamma(). Raymond Hettinger <python@rcn.com> parents: 23442 diff changeset	564 def stdgamma(self, alpha, ainv, bbb, ccc):
08ccb0f3e2d4 Closes patch 529408 deprecating random.stdgamma(). Raymond Hettinger <python@rcn.com> parents: 23442 diff changeset	565 # This method was (and shall remain) undocumented.
08ccb0f3e2d4 Closes patch 529408 deprecating random.stdgamma(). Raymond Hettinger <python@rcn.com> parents: 23442 diff changeset	566 # This method is deprecated
08ccb0f3e2d4 Closes patch 529408 deprecating random.stdgamma(). Raymond Hettinger <python@rcn.com> parents: 23442 diff changeset	567 # for the following reasons:
08ccb0f3e2d4 Closes patch 529408 deprecating random.stdgamma(). Raymond Hettinger <python@rcn.com> parents: 23442 diff changeset	568 # 1. Returns same as .gammavariate(alpha, 1.0)
08ccb0f3e2d4 Closes patch 529408 deprecating random.stdgamma(). Raymond Hettinger <python@rcn.com> parents: 23442 diff changeset	569 # 2. Requires caller to provide 3 extra arguments
08ccb0f3e2d4 Closes patch 529408 deprecating random.stdgamma(). Raymond Hettinger <python@rcn.com> parents: 23442 diff changeset	570 # that are functions of alpha anyway
08ccb0f3e2d4 Closes patch 529408 deprecating random.stdgamma(). Raymond Hettinger <python@rcn.com> parents: 23442 diff changeset	571 # 3. Can't be used for alpha < 0.5
08ccb0f3e2d4 Closes patch 529408 deprecating random.stdgamma(). Raymond Hettinger <python@rcn.com> parents: 23442 diff changeset	572
08ccb0f3e2d4 Closes patch 529408 deprecating random.stdgamma(). Raymond Hettinger <python@rcn.com> parents: 23442 diff changeset	573 # ainv = sqrt(2 * alpha - 1)
08ccb0f3e2d4 Closes patch 529408 deprecating random.stdgamma(). Raymond Hettinger <python@rcn.com> parents: 23442 diff changeset	574 # bbb = alpha - log(4)
08ccb0f3e2d4 Closes patch 529408 deprecating random.stdgamma(). Raymond Hettinger <python@rcn.com> parents: 23442 diff changeset	575 # ccc = alpha + ainv
08ccb0f3e2d4 Closes patch 529408 deprecating random.stdgamma(). Raymond Hettinger <python@rcn.com> parents: 23442 diff changeset	576 import warnings
08ccb0f3e2d4 Closes patch 529408 deprecating random.stdgamma(). Raymond Hettinger <python@rcn.com> parents: 23442 diff changeset	577 warnings.warn("The stdgamma function is deprecated; "
08ccb0f3e2d4 Closes patch 529408 deprecating random.stdgamma(). Raymond Hettinger <python@rcn.com> parents: 23442 diff changeset	578 "use gammavariate() instead",
08ccb0f3e2d4 Closes patch 529408 deprecating random.stdgamma(). Raymond Hettinger <python@rcn.com> parents: 23442 diff changeset	579 DeprecationWarning)
08ccb0f3e2d4 Closes patch 529408 deprecating random.stdgamma(). Raymond Hettinger <python@rcn.com> parents: 23442 diff changeset	580 return self.gammavariate(alpha, 1.0)
08ccb0f3e2d4 Closes patch 529408 deprecating random.stdgamma(). Raymond Hettinger <python@rcn.com> parents: 23442 diff changeset	581
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	582
1576 695fb494a3a2 Added gauss() (same as normal but twice as fast) and betavariate(); Guido van Rossum <guido@python.org> parents: 1575 diff changeset	583
16265 d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	584 ## -------------------- 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	585
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	586 def gauss(self, mu, sigma):
23531 a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	587 """Gaussian distribution.
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	588
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	589 mu is the mean, and sigma is the standard deviation. This is
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	590 slightly faster than the normalvariate() function.
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	591
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	592 Not thread-safe without a lock around calls.
23536 0a4c92559a0b Whitespace normalized. Raymond Hettinger <python@rcn.com> parents: 23531 diff changeset	593
23531 a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	594 """
1577 444e349f962f Use float constants directly; cosmetic changes; initialize largest Guido van Rossum <guido@python.org> parents: 1576 diff changeset	595
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	596 # 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	597 # 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	598 #
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	599 # 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	600 # 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	601 #
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	602 # 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	603 # (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	604 # (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	605 # (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	606
16242 3c5f09422b69 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 # 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	608 # 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	609 # 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	610 # 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	611 # 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	612 # lock here.)
1577 444e349f962f Use float constants directly; cosmetic changes; initialize largest Guido van Rossum <guido@python.org> parents: 1576 diff changeset	613
16242 3c5f09422b69 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 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	615 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	616 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	617 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	618 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	619 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	620 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	621 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	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 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	624
16265 d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	625 ## -------------------- beta --------------------
16271 7ef2382f6123 SF bug 130030: Claim of bad betavariate algorithm. Tim Peters <tim.peters@gmail.com> parents: 16265 diff changeset	626 ## See
7ef2382f6123 SF bug 130030: Claim of bad betavariate algorithm. Tim Peters <tim.peters@gmail.com> parents: 16265 diff changeset	627 ## 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	628 ## 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	629 ##
7ef2382f6123 SF bug 130030: Claim of bad betavariate algorithm. Tim Peters <tim.peters@gmail.com> parents: 16265 diff changeset	630 ## def betavariate(self, alpha, beta):
7ef2382f6123 SF bug 130030: Claim of bad betavariate algorithm. Tim Peters <tim.peters@gmail.com> parents: 16265 diff changeset	631 ## # 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	632 ##
7ef2382f6123 SF bug 130030: Claim of bad betavariate algorithm. Tim Peters <tim.peters@gmail.com> parents: 16265 diff changeset	633 ## y = self.expovariate(alpha)
7ef2382f6123 SF bug 130030: Claim of bad betavariate algorithm. Tim Peters <tim.peters@gmail.com> parents: 16265 diff changeset	634 ## 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	635 ## return z/(y+z)
7ef2382f6123 SF bug 130030: Claim of bad betavariate algorithm. Tim Peters <tim.peters@gmail.com> parents: 16265 diff changeset	636 ##
7ef2382f6123 SF bug 130030: Claim of bad betavariate algorithm. Tim Peters <tim.peters@gmail.com> parents: 16265 diff changeset	637 ## 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	638
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	639 def betavariate(self, alpha, beta):
23531 a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	640 """Beta distribution.
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	641
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	642 Conditions on the parameters are alpha > -1 and beta} > -1.
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	643 Returned values range between 0 and 1.
23536 0a4c92559a0b Whitespace normalized. Raymond Hettinger <python@rcn.com> parents: 23531 diff changeset	644
23531 a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	645 """
23536 0a4c92559a0b Whitespace normalized. Raymond Hettinger <python@rcn.com> parents: 23531 diff changeset	646
16271 7ef2382f6123 SF bug 130030: Claim of bad betavariate algorithm. Tim Peters <tim.peters@gmail.com> parents: 16265 diff changeset	647 # 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	648 # 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	649 y = self.gammavariate(alpha, 1.)
7ef2382f6123 SF bug 130030: Claim of bad betavariate algorithm. Tim Peters <tim.peters@gmail.com> parents: 16265 diff changeset	650 if y == 0:
7ef2382f6123 SF bug 130030: Claim of bad betavariate algorithm. Tim Peters <tim.peters@gmail.com> parents: 16265 diff changeset	651 return 0.0
7ef2382f6123 SF bug 130030: Claim of bad betavariate algorithm. Tim Peters <tim.peters@gmail.com> parents: 16265 diff changeset	652 else:
7ef2382f6123 SF bug 130030: Claim of bad betavariate algorithm. Tim Peters <tim.peters@gmail.com> parents: 16265 diff changeset	653 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	654
16265 d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	655 ## -------------------- Pareto --------------------
6698 b73eb4e6face Added Pareto and Weibull distributions, courtesy Jeremy Hylton. Guido van Rossum <guido@python.org> parents: 1618 diff changeset	656
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	657 def paretovariate(self, alpha):
23531 a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	658 """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	659 # Jain, pg. 495
6698 b73eb4e6face Added Pareto and Weibull distributions, courtesy Jeremy Hylton. Guido van Rossum <guido@python.org> parents: 1618 diff changeset	660
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	661 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	662 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	663
16265 d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	664 ## -------------------- Weibull --------------------
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 weibullvariate(self, alpha, beta):
23531 a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	667 """Weibull distribution.
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	668
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	669 alpha is the scale parameter and beta is the shape parameter.
23536 0a4c92559a0b Whitespace normalized. Raymond Hettinger <python@rcn.com> parents: 23531 diff changeset	670
23531 a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings. Raymond Hettinger <python@rcn.com> parents: 23521 diff changeset	671 """
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	672 # 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	673
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	674 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	675 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	676
16265 d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	677 ## -------------------- test program --------------------
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	678
16242 3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the Tim Peters <tim.peters@gmail.com> parents: 15871 diff changeset	679 def _test_generator(n, funccall):
15871 62aeefa01fdd Whitespace normalization. Tim Peters <tim.peters@gmail.com> parents: 14617 diff changeset	680 import time
62aeefa01fdd Whitespace normalization. Tim Peters <tim.peters@gmail.com> parents: 14617 diff changeset	681 print n, 'times', funccall
62aeefa01fdd Whitespace normalization. Tim Peters <tim.peters@gmail.com> parents: 14617 diff changeset	682 code = compile(funccall, funccall, 'eval')
62aeefa01fdd Whitespace normalization. Tim Peters <tim.peters@gmail.com> parents: 14617 diff changeset	683 sum = 0.0
62aeefa01fdd Whitespace normalization. Tim Peters <tim.peters@gmail.com> parents: 14617 diff changeset	684 sqsum = 0.0
62aeefa01fdd Whitespace normalization. Tim Peters <tim.peters@gmail.com> parents: 14617 diff changeset	685 smallest = 1e10
62aeefa01fdd Whitespace normalization. Tim Peters <tim.peters@gmail.com> parents: 14617 diff changeset	686 largest = -1e10
62aeefa01fdd Whitespace normalization. Tim Peters <tim.peters@gmail.com> parents: 14617 diff changeset	687 t0 = time.time()
62aeefa01fdd Whitespace normalization. Tim Peters <tim.peters@gmail.com> parents: 14617 diff changeset	688 for i in range(n):
62aeefa01fdd Whitespace normalization. Tim Peters <tim.peters@gmail.com> parents: 14617 diff changeset	689 x = eval(code)
62aeefa01fdd Whitespace normalization. Tim Peters <tim.peters@gmail.com> parents: 14617 diff changeset	690 sum = sum + x
62aeefa01fdd Whitespace normalization. Tim Peters <tim.peters@gmail.com> parents: 14617 diff changeset	691 sqsum = sqsum + x*x
62aeefa01fdd Whitespace normalization. Tim Peters <tim.peters@gmail.com> parents: 14617 diff changeset	692 smallest = min(x, smallest)
62aeefa01fdd Whitespace normalization. Tim Peters <tim.peters@gmail.com> parents: 14617 diff changeset	693 largest = max(x, largest)
62aeefa01fdd Whitespace normalization. Tim Peters <tim.peters@gmail.com> parents: 14617 diff changeset	694 t1 = time.time()
62aeefa01fdd Whitespace normalization. Tim Peters <tim.peters@gmail.com> parents: 14617 diff changeset	695 print round(t1-t0, 3), 'sec,',
62aeefa01fdd Whitespace normalization. Tim Peters <tim.peters@gmail.com> parents: 14617 diff changeset	696 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	697 stddev = _sqrt(sqsum/n - avg*avg)
15871 62aeefa01fdd Whitespace normalization. Tim Peters <tim.peters@gmail.com> parents: 14617 diff changeset	698 print 'avg %g, stddev %g, min %g, max %g' % \
62aeefa01fdd Whitespace normalization. Tim Peters <tim.peters@gmail.com> parents: 14617 diff changeset	699 (avg, stddev, smallest, largest)
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	700
23447 08ccb0f3e2d4 Closes patch 529408 deprecating random.stdgamma(). Raymond Hettinger <python@rcn.com> parents: 23442 diff changeset	701 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	702 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	703 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	704 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	705 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	706 _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	707 _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	708 _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	709 _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	710 _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	711 _test_generator(N, 'vonmisesvariate(0.0, 1.0)')
23447 08ccb0f3e2d4 Closes patch 529408 deprecating random.stdgamma(). Raymond Hettinger <python@rcn.com> parents: 23442 diff changeset	712 _test_generator(N, 'gammavariate(0.01, 1.0)')
08ccb0f3e2d4 Closes patch 529408 deprecating random.stdgamma(). Raymond Hettinger <python@rcn.com> parents: 23442 diff changeset	713 _test_generator(N, 'gammavariate(0.1, 1.0)')
23521 a90faa5f9417 Whitespace normalization. Tim Peters <tim.peters@gmail.com> parents: 23451 diff changeset	714 _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	715 _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	716 _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	717 _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	718 _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	719 _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	720 _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	721 _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	722 _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	723 _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	724 _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	725
16265 d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	726 # Test jumpahead.
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	727 s = getstate()
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	728 jumpahead(N)
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	729 r1 = random()
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	730 # 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	731 setstate(s)
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	732 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	733 random()
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	734 r2 = random()
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	735 if r1 != r2:
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics. Tim Peters <tim.peters@gmail.com> parents: 16243 diff changeset	736 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	737
16292 0501c2a10315 New comment block to Clarify a subtlety. Tim Peters <tim.peters@gmail.com> parents: 16272 diff changeset	738 # 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	739 # 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	740 # 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	741 # 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	742 # 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	743 _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	744 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	745 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	746 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	747 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	748 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	749 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	750 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	751 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	752 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	753 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	754 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	755 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	756 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	757 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	758 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	759 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	760 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	761 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	762 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	763 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	764 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	765 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	766
1575 45728bfecb76 Random variable generators Guido van Rossum <guido@python.org> parents: diff changeset	767 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	768 _test()

Mercurial > cpython-lru_cache-weakref

annotate Lib/random.py @ 24042:63fbbed10714 legacy-trunk