Mercurial > cpython-lru_cache-weakref

annotate Lib/random.py @ 32527:0da660e05e69 legacy-trunk

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
"#if WITH_THREAD" is incorrect; must be #ifdef instead; WITH_THREAD isn't always set to an integer value when it's defined.
author Tim Peters <tim.peters@gmail.com>
date Wed, 07 Jul 2004 20:42:07 +0000
parents 854a2417d35e
children 97fca735c8da
Ignore whitespace changes - Everywhere: Within whitespace: At end of lines:
rev   line source
11707
6f4146846337 The third and final doc-string sweep by Ka-Ping Yee.
Guido van Rossum <guido@python.org>
parents: 11200
diff changeset
1 """Random variable generators.
6f4146846337 The third and final doc-string sweep by Ka-Ping Yee.
Guido van Rossum <guido@python.org>
parents: 11200
diff changeset
2
16242
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the
Tim Peters <tim.peters@gmail.com>
parents: 15871
diff changeset
3 integers
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the
Tim Peters <tim.peters@gmail.com>
parents: 15871
diff changeset
4 --------
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the
Tim Peters <tim.peters@gmail.com>
parents: 15871
diff changeset
5 uniform within range
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the
Tim Peters <tim.peters@gmail.com>
parents: 15871
diff changeset
6
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the
Tim Peters <tim.peters@gmail.com>
parents: 15871
diff changeset
7 sequences
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the
Tim Peters <tim.peters@gmail.com>
parents: 15871
diff changeset
8 ---------
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the
Tim Peters <tim.peters@gmail.com>
parents: 15871
diff changeset
9 pick random element
26155
8ceb455f5541 SF patch 629637: Add sample(population, k) method to the random module.
Raymond Hettinger <python@rcn.com>
parents: 24861
diff changeset
10 pick random sample
16242
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the
Tim Peters <tim.peters@gmail.com>
parents: 15871
diff changeset
11 generate random permutation
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the
Tim Peters <tim.peters@gmail.com>
parents: 15871
diff changeset
12
11707
6f4146846337 The third and final doc-string sweep by Ka-Ping Yee.
Guido van Rossum <guido@python.org>
parents: 11200
diff changeset
13 distributions on the real line:
6f4146846337 The third and final doc-string sweep by Ka-Ping Yee.
Guido van Rossum <guido@python.org>
parents: 11200
diff changeset
14 ------------------------------
16242
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the
Tim Peters <tim.peters@gmail.com>
parents: 15871
diff changeset
15 uniform
11707
6f4146846337 The third and final doc-string sweep by Ka-Ping Yee.
Guido van Rossum <guido@python.org>
parents: 11200
diff changeset
16 normal (Gaussian)
6f4146846337 The third and final doc-string sweep by Ka-Ping Yee.
Guido van Rossum <guido@python.org>
parents: 11200
diff changeset
17 lognormal
6f4146846337 The third and final doc-string sweep by Ka-Ping Yee.
Guido van Rossum <guido@python.org>
parents: 11200
diff changeset
18 negative exponential
6f4146846337 The third and final doc-string sweep by Ka-Ping Yee.
Guido van Rossum <guido@python.org>
parents: 11200
diff changeset
19 gamma
6f4146846337 The third and final doc-string sweep by Ka-Ping Yee.
Guido van Rossum <guido@python.org>
parents: 11200
diff changeset
20 beta
26829
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
21 pareto
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
22 Weibull
1575
45728bfecb76 Random variable generators
Guido van Rossum <guido@python.org>
parents:
diff changeset
23
11707
6f4146846337 The third and final doc-string sweep by Ka-Ping Yee.
Guido van Rossum <guido@python.org>
parents: 11200
diff changeset
24 distributions on the circle (angles 0 to 2pi)
6f4146846337 The third and final doc-string sweep by Ka-Ping Yee.
Guido van Rossum <guido@python.org>
parents: 11200
diff changeset
25 ---------------------------------------------
6f4146846337 The third and final doc-string sweep by Ka-Ping Yee.
Guido van Rossum <guido@python.org>
parents: 11200
diff changeset
26 circular uniform
6f4146846337 The third and final doc-string sweep by Ka-Ping Yee.
Guido van Rossum <guido@python.org>
parents: 11200
diff changeset
27 von Mises
1575
45728bfecb76 Random variable generators
Guido van Rossum <guido@python.org>
parents:
diff changeset
28
26829
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
29 General notes on the underlying Mersenne Twister core generator:
16272
835e9dd54bfb The combo of getstate/setstate/jumpahead is very powerful, but needs
Tim Peters <tim.peters@gmail.com>
parents: 16271
diff changeset
30
26829
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
31 * The period is 2**19937-1.
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
32 * It is one of the most extensively tested generators in existence
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
33 * Without a direct way to compute N steps forward, the
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
34 semantics of jumpahead(n) are weakened to simply jump
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
35 to another distant state and rely on the large period
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
36 to avoid overlapping sequences.
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
37 * The random() method is implemented in C, executes in
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
38 a single Python step, and is, therefore, threadsafe.
16272
835e9dd54bfb The combo of getstate/setstate/jumpahead is very powerful, but needs
Tim Peters <tim.peters@gmail.com>
parents: 16271
diff changeset
39
11707
6f4146846337 The third and final doc-string sweep by Ka-Ping Yee.
Guido van Rossum <guido@python.org>
parents: 11200
diff changeset
40 """
16242
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the
Tim Peters <tim.peters@gmail.com>
parents: 15871
diff changeset
41
30649
8841d34a2c37 SF bug #812202: randint is always even
Raymond Hettinger <python@rcn.com>
parents: 30346
diff changeset
42 from warnings import warn as _warn
8841d34a2c37 SF bug #812202: randint is always even
Raymond Hettinger <python@rcn.com>
parents: 30346
diff changeset
43 from types import MethodType as _MethodType, BuiltinMethodType as _BuiltinMethodType
16242
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the
Tim Peters <tim.peters@gmail.com>
parents: 15871
diff changeset
44 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
45 from math import sqrt as _sqrt, acos as _acos, cos as _cos, sin as _sin
24861
4e795fe9f54b SF bug 594996: OverflowError in random.randrange
Tim Peters <tim.peters@gmail.com>
parents: 23536
diff changeset
46 from math import floor as _floor
8455
af9273b1073a Make gauss() semi-thread-safe. It can still give duplicate results,
Guido van Rossum <guido@python.org>
parents: 8393
diff changeset
47
26155
8ceb455f5541 SF patch 629637: Add sample(population, k) method to the random module.
Raymond Hettinger <python@rcn.com>
parents: 24861
diff changeset
48 __all__ = ["Random","seed","random","uniform","randint","choice","sample",
16613
f68dbffff927 bunch more __all__ lists
Skip Montanaro <skip@pobox.com>
parents: 16386
diff changeset
49 "randrange","shuffle","normalvariate","lognormvariate",
30068
171814f5dcc6 Removed deprecated functions
Raymond Hettinger <python@rcn.com>
parents: 29586
diff changeset
50 "expovariate","vonmisesvariate","gammavariate",
171814f5dcc6 Removed deprecated functions
Raymond Hettinger <python@rcn.com>
parents: 29586
diff changeset
51 "gauss","betavariate","paretovariate","weibullvariate",
30680
c226f84d7a66 Minor fixup. "Random" was listed twice in __all__.
Raymond Hettinger <python@rcn.com>
parents: 30649
diff changeset
52 "getstate","setstate","jumpahead", "WichmannHill", "getrandbits"]
1575
45728bfecb76 Random variable generators
Guido van Rossum <guido@python.org>
parents:
diff changeset
53
16242
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the
Tim Peters <tim.peters@gmail.com>
parents: 15871
diff changeset
54 NV_MAGICCONST = 4 * _exp(-0.5)/_sqrt(2.0)
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the
Tim Peters <tim.peters@gmail.com>
parents: 15871
diff changeset
55 TWOPI = 2.0*_pi
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the
Tim Peters <tim.peters@gmail.com>
parents: 15871
diff changeset
56 LOG4 = _log(4.0)
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the
Tim Peters <tim.peters@gmail.com>
parents: 15871
diff changeset
57 SG_MAGICCONST = 1.0 + _log(4.5)
30649
8841d34a2c37 SF bug #812202: randint is always even
Raymond Hettinger <python@rcn.com>
parents: 30346
diff changeset
58 BPF = 53 # Number of bits in a float
8393
7669ddf0e7d4 Add Interfaces to replace remaining needs for importing whrandom.
Guido van Rossum <guido@python.org>
parents: 7881
diff changeset
59
16242
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the
Tim Peters <tim.peters@gmail.com>
parents: 15871
diff changeset
60 # Translated by Guido van Rossum from C source provided by
26829
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
61 # Adrian Baddeley. Adapted by Raymond Hettinger for use with
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
62 # the Mersenne Twister core 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
63
27131
e87d590a5de1 Much clearer when super() is used.
Raymond Hettinger <python@rcn.com>
parents: 27094
diff changeset
64 import _random
26829
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
65
27131
e87d590a5de1 Much clearer when super() is used.
Raymond Hettinger <python@rcn.com>
parents: 27094
diff changeset
66 class Random(_random.Random):
23531
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings.
Raymond Hettinger <python@rcn.com>
parents: 23521
diff changeset
67 """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
68
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings.
Raymond Hettinger <python@rcn.com>
parents: 23521
diff changeset
69 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
70 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
71 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
72 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
73 overlap.
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings.
Raymond Hettinger <python@rcn.com>
parents: 23521
diff changeset
74
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings.
Raymond Hettinger <python@rcn.com>
parents: 23521
diff changeset
75 Class Random can also be subclassed if you want to use a different basic
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings.
Raymond Hettinger <python@rcn.com>
parents: 23521
diff changeset
76 generator of your own devising: in that case, override the following
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings.
Raymond Hettinger <python@rcn.com>
parents: 23521
diff changeset
77 methods: random(), seed(), getstate(), setstate() and jumpahead().
30649
8841d34a2c37 SF bug #812202: randint is always even
Raymond Hettinger <python@rcn.com>
parents: 30346
diff changeset
78 Optionally, implement a getrandombits() method so that randrange()
8841d34a2c37 SF bug #812202: randint is always even
Raymond Hettinger <python@rcn.com>
parents: 30346
diff changeset
79 can cover arbitrarily large ranges.
23536
0a4c92559a0b Whitespace normalized.
Raymond Hettinger <python@rcn.com>
parents: 23531
diff changeset
80
23531
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings.
Raymond Hettinger <python@rcn.com>
parents: 23521
diff changeset
81 """
8393
7669ddf0e7d4 Add Interfaces to replace remaining needs for importing whrandom.
Guido van Rossum <guido@python.org>
parents: 7881
diff changeset
82
26829
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
83 VERSION = 2 # used by getstate/setstate
16242
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the
Tim Peters <tim.peters@gmail.com>
parents: 15871
diff changeset
84
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the
Tim Peters <tim.peters@gmail.com>
parents: 15871
diff changeset
85 def __init__(self, x=None):
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the
Tim Peters <tim.peters@gmail.com>
parents: 15871
diff changeset
86 """Initialize an instance.
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the
Tim Peters <tim.peters@gmail.com>
parents: 15871
diff changeset
87
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the
Tim Peters <tim.peters@gmail.com>
parents: 15871
diff changeset
88 Optional argument x controls seeding, as for Random.seed().
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the
Tim Peters <tim.peters@gmail.com>
parents: 15871
diff changeset
89 """
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the
Tim Peters <tim.peters@gmail.com>
parents: 15871
diff changeset
90
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the
Tim Peters <tim.peters@gmail.com>
parents: 15871
diff changeset
91 self.seed(x)
26829
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
92 self.gauss_next = None
16242
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the
Tim Peters <tim.peters@gmail.com>
parents: 15871
diff changeset
93
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
94 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
95 """Initialize internal state from hashable object.
5f0683a69efc Change random.seed() so that it can get at the full range of possible
Tim Peters <tim.peters@gmail.com>
parents: 16292
diff changeset
96
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
97 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
98
16386
c2555b4f38a3 Repaired a docstring.
Tim Peters <tim.peters@gmail.com>
parents: 16379
diff changeset
99 If a is not None or an int or long, hash(a) is used instead.
16242
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the
Tim Peters <tim.peters@gmail.com>
parents: 15871
diff changeset
100 """
8393
7669ddf0e7d4 Add Interfaces to replace remaining needs for importing whrandom.
Guido van Rossum <guido@python.org>
parents: 7881
diff changeset
101
30114
9f6e2dee1892 SF bug #778964: bad seed in python 2.3 random
Raymond Hettinger <python@rcn.com>
parents: 30068
diff changeset
102 if a is None:
9f6e2dee1892 SF bug #778964: bad seed in python 2.3 random
Raymond Hettinger <python@rcn.com>
parents: 30068
diff changeset
103 import time
9f6e2dee1892 SF bug #778964: bad seed in python 2.3 random
Raymond Hettinger <python@rcn.com>
parents: 30068
diff changeset
104 a = long(time.time() * 256) # use fractional seconds
27131
e87d590a5de1 Much clearer when super() is used.
Raymond Hettinger <python@rcn.com>
parents: 27094
diff changeset
105 super(Random, self).seed(a)
23380
9be01b7b6c80 random.gauss() uses a piece of hidden state used by nothing else,
Tim Peters <tim.peters@gmail.com>
parents: 23023
diff changeset
106 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
107
16265
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics.
Tim Peters <tim.peters@gmail.com>
parents: 16243
diff changeset
108 def getstate(self):
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics.
Tim Peters <tim.peters@gmail.com>
parents: 16243
diff changeset
109 """Return internal state; can be passed to setstate() later."""
27131
e87d590a5de1 Much clearer when super() is used.
Raymond Hettinger <python@rcn.com>
parents: 27094
diff changeset
110 return self.VERSION, super(Random, self).getstate(), self.gauss_next
16265
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics.
Tim Peters <tim.peters@gmail.com>
parents: 16243
diff changeset
111
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics.
Tim Peters <tim.peters@gmail.com>
parents: 16243
diff changeset
112 def setstate(self, state):
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics.
Tim Peters <tim.peters@gmail.com>
parents: 16243
diff changeset
113 """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
114 version = state[0]
26829
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
115 if version == 2:
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
116 version, internalstate, self.gauss_next = state
27131
e87d590a5de1 Much clearer when super() is used.
Raymond Hettinger <python@rcn.com>
parents: 27094
diff changeset
117 super(Random, self).setstate(internalstate)
16265
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics.
Tim Peters <tim.peters@gmail.com>
parents: 16243
diff changeset
118 else:
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics.
Tim Peters <tim.peters@gmail.com>
parents: 16243
diff changeset
119 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
120 "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
121 (version, self.VERSION))
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics.
Tim Peters <tim.peters@gmail.com>
parents: 16243
diff changeset
122
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics.
Tim Peters <tim.peters@gmail.com>
parents: 16243
diff changeset
123 ## ---- 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
124 ## ---- 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
125
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics.
Tim Peters <tim.peters@gmail.com>
parents: 16243
diff changeset
126 ## -------------------- pickle support -------------------
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics.
Tim Peters <tim.peters@gmail.com>
parents: 16243
diff changeset
127
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics.
Tim Peters <tim.peters@gmail.com>
parents: 16243
diff changeset
128 def __getstate__(self): # for pickle
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics.
Tim Peters <tim.peters@gmail.com>
parents: 16243
diff changeset
129 return self.getstate()
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics.
Tim Peters <tim.peters@gmail.com>
parents: 16243
diff changeset
130
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics.
Tim Peters <tim.peters@gmail.com>
parents: 16243
diff changeset
131 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
132 self.setstate(state)
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics.
Tim Peters <tim.peters@gmail.com>
parents: 16243
diff changeset
133
29586
8b163370372d SF bug #759889: Pickling of Random is broken
Raymond Hettinger <python@rcn.com>
parents: 29539
diff changeset
134 def __reduce__(self):
8b163370372d SF bug #759889: Pickling of Random is broken
Raymond Hettinger <python@rcn.com>
parents: 29539
diff changeset
135 return self.__class__, (), self.getstate()
8b163370372d SF bug #759889: Pickling of Random is broken
Raymond Hettinger <python@rcn.com>
parents: 29539
diff changeset
136
16265
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics.
Tim Peters <tim.peters@gmail.com>
parents: 16243
diff changeset
137 ## -------------------- integer methods -------------------
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics.
Tim Peters <tim.peters@gmail.com>
parents: 16243
diff changeset
138
30649
8841d34a2c37 SF bug #812202: randint is always even
Raymond Hettinger <python@rcn.com>
parents: 30346
diff changeset
139 def randrange(self, start, stop=None, step=1, int=int, default=None,
8841d34a2c37 SF bug #812202: randint is always even
Raymond Hettinger <python@rcn.com>
parents: 30346
diff changeset
140 maxwidth=1L<<BPF):
16242
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the
Tim Peters <tim.peters@gmail.com>
parents: 15871
diff changeset
141 """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
142
16242
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the
Tim Peters <tim.peters@gmail.com>
parents: 15871
diff changeset
143 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
144 endpoint; in Python this is usually not what you want.
30649
8841d34a2c37 SF bug #812202: randint is always even
Raymond Hettinger <python@rcn.com>
parents: 30346
diff changeset
145 Do not supply the 'int', 'default', and 'maxwidth' arguments.
16242
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the
Tim Peters <tim.peters@gmail.com>
parents: 15871
diff changeset
146 """
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the
Tim Peters <tim.peters@gmail.com>
parents: 15871
diff changeset
147
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the
Tim Peters <tim.peters@gmail.com>
parents: 15871
diff changeset
148 # This code is a bit messy to make it fast for the
24861
4e795fe9f54b SF bug 594996: OverflowError in random.randrange
Tim Peters <tim.peters@gmail.com>
parents: 23536
diff changeset
149 # common case while still doing adequate error checking.
16242
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the
Tim Peters <tim.peters@gmail.com>
parents: 15871
diff changeset
150 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
151 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
152 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
153 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
154 if istart > 0:
30649
8841d34a2c37 SF bug #812202: randint is always even
Raymond Hettinger <python@rcn.com>
parents: 30346
diff changeset
155 if istart >= maxwidth:
8841d34a2c37 SF bug #812202: randint is always even
Raymond Hettinger <python@rcn.com>
parents: 30346
diff changeset
156 return self._randbelow(istart)
16242
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the
Tim Peters <tim.peters@gmail.com>
parents: 15871
diff changeset
157 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
158 raise ValueError, "empty range for randrange()"
24861
4e795fe9f54b SF bug 594996: OverflowError in random.randrange
Tim Peters <tim.peters@gmail.com>
parents: 23536
diff changeset
159
4e795fe9f54b SF bug 594996: OverflowError in random.randrange
Tim Peters <tim.peters@gmail.com>
parents: 23536
diff changeset
160 # stop argument supplied.
16242
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the
Tim Peters <tim.peters@gmail.com>
parents: 15871
diff changeset
161 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
162 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
163 raise ValueError, "non-integer stop for randrange()"
30649
8841d34a2c37 SF bug #812202: randint is always even
Raymond Hettinger <python@rcn.com>
parents: 30346
diff changeset
164 width = istop - istart
8841d34a2c37 SF bug #812202: randint is always even
Raymond Hettinger <python@rcn.com>
parents: 30346
diff changeset
165 if step == 1 and width > 0:
29539
fafb6eb0f97e randrange(): Repaired my overly optimistic rewrite, and added comments
Tim Peters <tim.peters@gmail.com>
parents: 29538
diff changeset
166 # Note that
30649
8841d34a2c37 SF bug #812202: randint is always even
Raymond Hettinger <python@rcn.com>
parents: 30346
diff changeset
167 # int(istart + self.random()*width)
29539
fafb6eb0f97e randrange(): Repaired my overly optimistic rewrite, and added comments
Tim Peters <tim.peters@gmail.com>
parents: 29538
diff changeset
168 # instead would be incorrect. For example, consider istart
fafb6eb0f97e randrange(): Repaired my overly optimistic rewrite, and added comments
Tim Peters <tim.peters@gmail.com>
parents: 29538
diff changeset
169 # = -2 and istop = 0. Then the guts would be in
fafb6eb0f97e randrange(): Repaired my overly optimistic rewrite, and added comments
Tim Peters <tim.peters@gmail.com>
parents: 29538
diff changeset
170 # -2.0 to 0.0 exclusive on both ends (ignoring that random()
fafb6eb0f97e randrange(): Repaired my overly optimistic rewrite, and added comments
Tim Peters <tim.peters@gmail.com>
parents: 29538
diff changeset
171 # might return 0.0), and because int() truncates toward 0, the
fafb6eb0f97e randrange(): Repaired my overly optimistic rewrite, and added comments
Tim Peters <tim.peters@gmail.com>
parents: 29538
diff changeset
172 # final result would be -1 or 0 (instead of -2 or -1).
30649
8841d34a2c37 SF bug #812202: randint is always even
Raymond Hettinger <python@rcn.com>
parents: 30346
diff changeset
173 # istart + int(self.random()*width)
29539
fafb6eb0f97e randrange(): Repaired my overly optimistic rewrite, and added comments
Tim Peters <tim.peters@gmail.com>
parents: 29538
diff changeset
174 # would also be incorrect, for a subtler reason: the RHS
fafb6eb0f97e randrange(): Repaired my overly optimistic rewrite, and added comments
Tim Peters <tim.peters@gmail.com>
parents: 29538
diff changeset
175 # can return a long, and then randrange() would also return
fafb6eb0f97e randrange(): Repaired my overly optimistic rewrite, and added comments
Tim Peters <tim.peters@gmail.com>
parents: 29538
diff changeset
176 # a long, but we're supposed to return an int (for backward
fafb6eb0f97e randrange(): Repaired my overly optimistic rewrite, and added comments
Tim Peters <tim.peters@gmail.com>
parents: 29538
diff changeset
177 # compatibility).
30649
8841d34a2c37 SF bug #812202: randint is always even
Raymond Hettinger <python@rcn.com>
parents: 30346
diff changeset
178
8841d34a2c37 SF bug #812202: randint is always even
Raymond Hettinger <python@rcn.com>
parents: 30346
diff changeset
179 if width >= maxwidth:
31389
aca1ce1b4b61 Whitespace normalization.
Tim Peters <tim.peters@gmail.com>
parents: 30865
diff changeset
180 return int(istart + self._randbelow(width))
30649
8841d34a2c37 SF bug #812202: randint is always even
Raymond Hettinger <python@rcn.com>
parents: 30346
diff changeset
181 return int(istart + int(self.random()*width))
16242
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the
Tim Peters <tim.peters@gmail.com>
parents: 15871
diff changeset
182 if step == 1:
30649
8841d34a2c37 SF bug #812202: randint is always even
Raymond Hettinger <python@rcn.com>
parents: 30346
diff changeset
183 raise ValueError, "empty range for randrange() (%d,%d, %d)" % (istart, istop, width)
24861
4e795fe9f54b SF bug 594996: OverflowError in random.randrange
Tim Peters <tim.peters@gmail.com>
parents: 23536
diff changeset
184
4e795fe9f54b SF bug 594996: OverflowError in random.randrange
Tim Peters <tim.peters@gmail.com>
parents: 23536
diff changeset
185 # Non-unit step argument supplied.
16242
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the
Tim Peters <tim.peters@gmail.com>
parents: 15871
diff changeset
186 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
187 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
188 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
189 if istep > 0:
30649
8841d34a2c37 SF bug #812202: randint is always even
Raymond Hettinger <python@rcn.com>
parents: 30346
diff changeset
190 n = (width + istep - 1) / istep
16242
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the
Tim Peters <tim.peters@gmail.com>
parents: 15871
diff changeset
191 elif istep < 0:
30649
8841d34a2c37 SF bug #812202: randint is always even
Raymond Hettinger <python@rcn.com>
parents: 30346
diff changeset
192 n = (width + istep + 1) / istep
16242
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the
Tim Peters <tim.peters@gmail.com>
parents: 15871
diff changeset
193 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
194 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
195
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the
Tim Peters <tim.peters@gmail.com>
parents: 15871
diff changeset
196 if 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
197 raise ValueError, "empty range for randrange()"
30649
8841d34a2c37 SF bug #812202: randint is always even
Raymond Hettinger <python@rcn.com>
parents: 30346
diff changeset
198
8841d34a2c37 SF bug #812202: randint is always even
Raymond Hettinger <python@rcn.com>
parents: 30346
diff changeset
199 if n >= maxwidth:
8841d34a2c37 SF bug #812202: randint is always even
Raymond Hettinger <python@rcn.com>
parents: 30346
diff changeset
200 return istart + self._randbelow(n)
16242
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the
Tim Peters <tim.peters@gmail.com>
parents: 15871
diff changeset
201 return istart + istep*int(self.random() * n)
1575
45728bfecb76 Random variable generators
Guido van Rossum <guido@python.org>
parents:
diff changeset
202
16242
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the
Tim Peters <tim.peters@gmail.com>
parents: 15871
diff changeset
203 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
204 """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
205 """
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the
Tim Peters <tim.peters@gmail.com>
parents: 15871
diff changeset
206
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the
Tim Peters <tim.peters@gmail.com>
parents: 15871
diff changeset
207 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
208
30649
8841d34a2c37 SF bug #812202: randint is always even
Raymond Hettinger <python@rcn.com>
parents: 30346
diff changeset
209 def _randbelow(self, n, _log=_log, int=int, _maxwidth=1L<<BPF,
8841d34a2c37 SF bug #812202: randint is always even
Raymond Hettinger <python@rcn.com>
parents: 30346
diff changeset
210 _Method=_MethodType, _BuiltinMethod=_BuiltinMethodType):
8841d34a2c37 SF bug #812202: randint is always even
Raymond Hettinger <python@rcn.com>
parents: 30346
diff changeset
211 """Return a random int in the range [0,n)
8841d34a2c37 SF bug #812202: randint is always even
Raymond Hettinger <python@rcn.com>
parents: 30346
diff changeset
212
8841d34a2c37 SF bug #812202: randint is always even
Raymond Hettinger <python@rcn.com>
parents: 30346
diff changeset
213 Handles the case where n has more bits than returned
8841d34a2c37 SF bug #812202: randint is always even
Raymond Hettinger <python@rcn.com>
parents: 30346
diff changeset
214 by a single call to the underlying generator.
8841d34a2c37 SF bug #812202: randint is always even
Raymond Hettinger <python@rcn.com>
parents: 30346
diff changeset
215 """
8841d34a2c37 SF bug #812202: randint is always even
Raymond Hettinger <python@rcn.com>
parents: 30346
diff changeset
216
8841d34a2c37 SF bug #812202: randint is always even
Raymond Hettinger <python@rcn.com>
parents: 30346
diff changeset
217 try:
8841d34a2c37 SF bug #812202: randint is always even
Raymond Hettinger <python@rcn.com>
parents: 30346
diff changeset
218 getrandbits = self.getrandbits
8841d34a2c37 SF bug #812202: randint is always even
Raymond Hettinger <python@rcn.com>
parents: 30346
diff changeset
219 except AttributeError:
8841d34a2c37 SF bug #812202: randint is always even
Raymond Hettinger <python@rcn.com>
parents: 30346
diff changeset
220 pass
8841d34a2c37 SF bug #812202: randint is always even
Raymond Hettinger <python@rcn.com>
parents: 30346
diff changeset
221 else:
8841d34a2c37 SF bug #812202: randint is always even
Raymond Hettinger <python@rcn.com>
parents: 30346
diff changeset
222 # Only call self.getrandbits if the original random() builtin method
8841d34a2c37 SF bug #812202: randint is always even
Raymond Hettinger <python@rcn.com>
parents: 30346
diff changeset
223 # has not been overridden or if a new getrandbits() was supplied.
8841d34a2c37 SF bug #812202: randint is always even
Raymond Hettinger <python@rcn.com>
parents: 30346
diff changeset
224 # This assures that the two methods correspond.
8841d34a2c37 SF bug #812202: randint is always even
Raymond Hettinger <python@rcn.com>
parents: 30346
diff changeset
225 if type(self.random) is _BuiltinMethod or type(getrandbits) is _Method:
8841d34a2c37 SF bug #812202: randint is always even
Raymond Hettinger <python@rcn.com>
parents: 30346
diff changeset
226 k = int(1.00001 + _log(n-1, 2.0)) # 2**k > n-1 > 2**(k-2)
8841d34a2c37 SF bug #812202: randint is always even
Raymond Hettinger <python@rcn.com>
parents: 30346
diff changeset
227 r = getrandbits(k)
8841d34a2c37 SF bug #812202: randint is always even
Raymond Hettinger <python@rcn.com>
parents: 30346
diff changeset
228 while r >= n:
8841d34a2c37 SF bug #812202: randint is always even
Raymond Hettinger <python@rcn.com>
parents: 30346
diff changeset
229 r = getrandbits(k)
8841d34a2c37 SF bug #812202: randint is always even
Raymond Hettinger <python@rcn.com>
parents: 30346
diff changeset
230 return r
8841d34a2c37 SF bug #812202: randint is always even
Raymond Hettinger <python@rcn.com>
parents: 30346
diff changeset
231 if n >= _maxwidth:
8841d34a2c37 SF bug #812202: randint is always even
Raymond Hettinger <python@rcn.com>
parents: 30346
diff changeset
232 _warn("Underlying random() generator does not supply \n"
8841d34a2c37 SF bug #812202: randint is always even
Raymond Hettinger <python@rcn.com>
parents: 30346
diff changeset
233 "enough bits to choose from a population range this large")
8841d34a2c37 SF bug #812202: randint is always even
Raymond Hettinger <python@rcn.com>
parents: 30346
diff changeset
234 return int(self.random() * n)
8841d34a2c37 SF bug #812202: randint is always even
Raymond Hettinger <python@rcn.com>
parents: 30346
diff changeset
235
16265
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics.
Tim Peters <tim.peters@gmail.com>
parents: 16243
diff changeset
236 ## -------------------- sequence methods -------------------
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics.
Tim Peters <tim.peters@gmail.com>
parents: 16243
diff changeset
237
16242
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the
Tim Peters <tim.peters@gmail.com>
parents: 15871
diff changeset
238 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
239 """Choose a random element from a non-empty sequence."""
32287
854a2417d35e Fix typo in comment.
Raymond Hettinger <python@rcn.com>
parents: 32255
diff changeset
240 return seq[int(self.random() * len(seq))] # raises IndexError if seq is empty
16242
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the
Tim Peters <tim.peters@gmail.com>
parents: 15871
diff changeset
241
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the
Tim Peters <tim.peters@gmail.com>
parents: 15871
diff changeset
242 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
243 """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
244
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the
Tim Peters <tim.peters@gmail.com>
parents: 15871
diff changeset
245 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
246 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
247
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the
Tim Peters <tim.peters@gmail.com>
parents: 15871
diff changeset
248 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
249 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
250 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
251 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
252 """
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the
Tim Peters <tim.peters@gmail.com>
parents: 15871
diff changeset
253
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the
Tim Peters <tim.peters@gmail.com>
parents: 15871
diff changeset
254 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
255 random = self.random
30865
41c4e143e6e6 Implement and apply PEP 322, reverse iteration
Raymond Hettinger <python@rcn.com>
parents: 30680
diff changeset
256 for i in reversed(xrange(1, len(x))):
16265
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics.
Tim Peters <tim.peters@gmail.com>
parents: 16243
diff changeset
257 # 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
258 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
259 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
260
29430
b80a22250e4f SF bug #753602: random.sample not properly documented
Raymond Hettinger <python@rcn.com>
parents: 29250
diff changeset
261 def sample(self, population, k):
26155
8ceb455f5541 SF patch 629637: Add sample(population, k) method to the random module.
Raymond Hettinger <python@rcn.com>
parents: 24861
diff changeset
262 """Chooses k unique random elements from a population sequence.
8ceb455f5541 SF patch 629637: Add sample(population, k) method to the random module.
Raymond Hettinger <python@rcn.com>
parents: 24861
diff changeset
263
26178
83ae4a902df0 Improved clarity and thoroughness of docstring.
Raymond Hettinger <python@rcn.com>
parents: 26172
diff changeset
264 Returns a new list containing elements from the population while
83ae4a902df0 Improved clarity and thoroughness of docstring.
Raymond Hettinger <python@rcn.com>
parents: 26172
diff changeset
265 leaving the original population unchanged. The resulting list is
83ae4a902df0 Improved clarity and thoroughness of docstring.
Raymond Hettinger <python@rcn.com>
parents: 26172
diff changeset
266 in selection order so that all sub-slices will also be valid random
83ae4a902df0 Improved clarity and thoroughness of docstring.
Raymond Hettinger <python@rcn.com>
parents: 26172
diff changeset
267 samples. This allows raffle winners (the sample) to be partitioned
83ae4a902df0 Improved clarity and thoroughness of docstring.
Raymond Hettinger <python@rcn.com>
parents: 26172
diff changeset
268 into grand prize and second place winners (the subslices).
26155
8ceb455f5541 SF patch 629637: Add sample(population, k) method to the random module.
Raymond Hettinger <python@rcn.com>
parents: 24861
diff changeset
269
26178
83ae4a902df0 Improved clarity and thoroughness of docstring.
Raymond Hettinger <python@rcn.com>
parents: 26172
diff changeset
270 Members of the population need not be hashable or unique. If the
83ae4a902df0 Improved clarity and thoroughness of docstring.
Raymond Hettinger <python@rcn.com>
parents: 26172
diff changeset
271 population contains repeats, then each occurrence is a possible
83ae4a902df0 Improved clarity and thoroughness of docstring.
Raymond Hettinger <python@rcn.com>
parents: 26172
diff changeset
272 selection in the sample.
26155
8ceb455f5541 SF patch 629637: Add sample(population, k) method to the random module.
Raymond Hettinger <python@rcn.com>
parents: 24861
diff changeset
273
26178
83ae4a902df0 Improved clarity and thoroughness of docstring.
Raymond Hettinger <python@rcn.com>
parents: 26172
diff changeset
274 To choose a sample in a range of integers, use xrange as an argument.
83ae4a902df0 Improved clarity and thoroughness of docstring.
Raymond Hettinger <python@rcn.com>
parents: 26172
diff changeset
275 This is especially fast and space efficient for sampling from a
83ae4a902df0 Improved clarity and thoroughness of docstring.
Raymond Hettinger <python@rcn.com>
parents: 26172
diff changeset
276 large population: sample(xrange(10000000), 60)
26155
8ceb455f5541 SF patch 629637: Add sample(population, k) method to the random module.
Raymond Hettinger <python@rcn.com>
parents: 24861
diff changeset
277 """
8ceb455f5541 SF patch 629637: Add sample(population, k) method to the random module.
Raymond Hettinger <python@rcn.com>
parents: 24861
diff changeset
278
26178
83ae4a902df0 Improved clarity and thoroughness of docstring.
Raymond Hettinger <python@rcn.com>
parents: 26172
diff changeset
279 # Sampling without replacement entails tracking either potential
27080
2ae1d17572da Remove the random=None nonsense from sample() before it gets set in stone.
Raymond Hettinger <python@rcn.com>
parents: 26829
diff changeset
280 # selections (the pool) in a list or previous selections in a
2ae1d17572da Remove the random=None nonsense from sample() before it gets set in stone.
Raymond Hettinger <python@rcn.com>
parents: 26829
diff changeset
281 # dictionary.
26178
83ae4a902df0 Improved clarity and thoroughness of docstring.
Raymond Hettinger <python@rcn.com>
parents: 26172
diff changeset
282
31578
8183dd1a4fe6 Reflow long line.
Jeremy Hylton <jeremy@alum.mit.edu>
parents: 31389
diff changeset
283 # When the number of selections is small compared to the
8183dd1a4fe6 Reflow long line.
Jeremy Hylton <jeremy@alum.mit.edu>
parents: 31389
diff changeset
284 # population, then tracking selections is efficient, requiring
8183dd1a4fe6 Reflow long line.
Jeremy Hylton <jeremy@alum.mit.edu>
parents: 31389
diff changeset
285 # only a small dictionary and an occasional reselection. For
8183dd1a4fe6 Reflow long line.
Jeremy Hylton <jeremy@alum.mit.edu>
parents: 31389
diff changeset
286 # a larger number of selections, the pool tracking method is
8183dd1a4fe6 Reflow long line.
Jeremy Hylton <jeremy@alum.mit.edu>
parents: 31389
diff changeset
287 # preferred since the list takes less space than the
8183dd1a4fe6 Reflow long line.
Jeremy Hylton <jeremy@alum.mit.edu>
parents: 31389
diff changeset
288 # dictionary and it doesn't suffer from frequent reselections.
26178
83ae4a902df0 Improved clarity and thoroughness of docstring.
Raymond Hettinger <python@rcn.com>
parents: 26172
diff changeset
289
26155
8ceb455f5541 SF patch 629637: Add sample(population, k) method to the random module.
Raymond Hettinger <python@rcn.com>
parents: 24861
diff changeset
290 n = len(population)
8ceb455f5541 SF patch 629637: Add sample(population, k) method to the random module.
Raymond Hettinger <python@rcn.com>
parents: 24861
diff changeset
291 if not 0 <= k <= n:
8ceb455f5541 SF patch 629637: Add sample(population, k) method to the random module.
Raymond Hettinger <python@rcn.com>
parents: 24861
diff changeset
292 raise ValueError, "sample larger than population"
27080
2ae1d17572da Remove the random=None nonsense from sample() before it gets set in stone.
Raymond Hettinger <python@rcn.com>
parents: 26829
diff changeset
293 random = self.random
29430
b80a22250e4f SF bug #753602: random.sample not properly documented
Raymond Hettinger <python@rcn.com>
parents: 29250
diff changeset
294 _int = int
26178
83ae4a902df0 Improved clarity and thoroughness of docstring.
Raymond Hettinger <python@rcn.com>
parents: 26172
diff changeset
295 result = [None] * k
26155
8ceb455f5541 SF patch 629637: Add sample(population, k) method to the random module.
Raymond Hettinger <python@rcn.com>
parents: 24861
diff changeset
296 if n < 6 * k: # if n len list takes less space than a k len dict
26266
42279f7d244d Improve comments. Clarify docs.
Raymond Hettinger <python@rcn.com>
parents: 26178
diff changeset
297 pool = list(population)
42279f7d244d Improve comments. Clarify docs.
Raymond Hettinger <python@rcn.com>
parents: 26178
diff changeset
298 for i in xrange(k): # invariant: non-selected at [0,n-i)
29430
b80a22250e4f SF bug #753602: random.sample not properly documented
Raymond Hettinger <python@rcn.com>
parents: 29250
diff changeset
299 j = _int(random() * (n-i))
26266
42279f7d244d Improve comments. Clarify docs.
Raymond Hettinger <python@rcn.com>
parents: 26178
diff changeset
300 result[i] = pool[j]
27080
2ae1d17572da Remove the random=None nonsense from sample() before it gets set in stone.
Raymond Hettinger <python@rcn.com>
parents: 26829
diff changeset
301 pool[j] = pool[n-i-1] # move non-selected item into vacancy
26178
83ae4a902df0 Improved clarity and thoroughness of docstring.
Raymond Hettinger <python@rcn.com>
parents: 26172
diff changeset
302 else:
30346
aaf6b6a8510b SF bug #801342: Bug (documentation or real, your choice) in random.sample.
Raymond Hettinger <python@rcn.com>
parents: 30243
diff changeset
303 try:
aaf6b6a8510b SF bug #801342: Bug (documentation or real, your choice) in random.sample.
Raymond Hettinger <python@rcn.com>
parents: 30243
diff changeset
304 n > 0 and (population[0], population[n//2], population[n-1])
aaf6b6a8510b SF bug #801342: Bug (documentation or real, your choice) in random.sample.
Raymond Hettinger <python@rcn.com>
parents: 30243
diff changeset
305 except (TypeError, KeyError): # handle sets and dictionaries
aaf6b6a8510b SF bug #801342: Bug (documentation or real, your choice) in random.sample.
Raymond Hettinger <python@rcn.com>
parents: 30243
diff changeset
306 population = tuple(population)
26266
42279f7d244d Improve comments. Clarify docs.
Raymond Hettinger <python@rcn.com>
parents: 26178
diff changeset
307 selected = {}
26178
83ae4a902df0 Improved clarity and thoroughness of docstring.
Raymond Hettinger <python@rcn.com>
parents: 26172
diff changeset
308 for i in xrange(k):
29430
b80a22250e4f SF bug #753602: random.sample not properly documented
Raymond Hettinger <python@rcn.com>
parents: 29250
diff changeset
309 j = _int(random() * n)
26266
42279f7d244d Improve comments. Clarify docs.
Raymond Hettinger <python@rcn.com>
parents: 26178
diff changeset
310 while j in selected:
29430
b80a22250e4f SF bug #753602: random.sample not properly documented
Raymond Hettinger <python@rcn.com>
parents: 29250
diff changeset
311 j = _int(random() * n)
26178
83ae4a902df0 Improved clarity and thoroughness of docstring.
Raymond Hettinger <python@rcn.com>
parents: 26172
diff changeset
312 result[i] = selected[j] = population[j]
26266
42279f7d244d Improve comments. Clarify docs.
Raymond Hettinger <python@rcn.com>
parents: 26178
diff changeset
313 return result
26155
8ceb455f5541 SF patch 629637: Add sample(population, k) method to the random module.
Raymond Hettinger <python@rcn.com>
parents: 24861
diff changeset
314
16265
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics.
Tim Peters <tim.peters@gmail.com>
parents: 16243
diff changeset
315 ## -------------------- real-valued distributions -------------------
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics.
Tim Peters <tim.peters@gmail.com>
parents: 16243
diff changeset
316
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics.
Tim Peters <tim.peters@gmail.com>
parents: 16243
diff changeset
317 ## -------------------- 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
318
3c5f09422b69 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 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
320 """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
321 return a + (b-a) * self.random()
1575
45728bfecb76 Random variable generators
Guido van Rossum <guido@python.org>
parents:
diff changeset
322
16265
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics.
Tim Peters <tim.peters@gmail.com>
parents: 16243
diff changeset
323 ## -------------------- normal distribution --------------------
1575
45728bfecb76 Random variable generators
Guido van Rossum <guido@python.org>
parents:
diff changeset
324
16242
3c5f09422b69 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 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
326 """Normal distribution.
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings.
Raymond Hettinger <python@rcn.com>
parents: 23521
diff changeset
327
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings.
Raymond Hettinger <python@rcn.com>
parents: 23521
diff changeset
328 mu is the mean, and sigma is the standard deviation.
23536
0a4c92559a0b Whitespace normalized.
Raymond Hettinger <python@rcn.com>
parents: 23531
diff changeset
329
23531
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings.
Raymond Hettinger <python@rcn.com>
parents: 23521
diff changeset
330 """
16242
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the
Tim Peters <tim.peters@gmail.com>
parents: 15871
diff changeset
331 # 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
332
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the
Tim Peters <tim.peters@gmail.com>
parents: 15871
diff changeset
333 # 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
334 # 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
335 # 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
336 # Math Software, 3, (1977), pp257-260.
1575
45728bfecb76 Random variable generators
Guido van Rossum <guido@python.org>
parents:
diff changeset
337
16242
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the
Tim Peters <tim.peters@gmail.com>
parents: 15871
diff changeset
338 random = self.random
26266
42279f7d244d Improve comments. Clarify docs.
Raymond Hettinger <python@rcn.com>
parents: 26178
diff changeset
339 while True:
16242
3c5f09422b69 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 u1 = random()
27085
90350b5d3397 Correct long standing bugs in the methods for random distributions.
Raymond Hettinger <python@rcn.com>
parents: 27080
diff changeset
341 u2 = 1.0 - random()
16242
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the
Tim Peters <tim.peters@gmail.com>
parents: 15871
diff changeset
342 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
343 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
344 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
345 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
346 return mu + z*sigma
1575
45728bfecb76 Random variable generators
Guido van Rossum <guido@python.org>
parents:
diff changeset
347
16265
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics.
Tim Peters <tim.peters@gmail.com>
parents: 16243
diff changeset
348 ## -------------------- lognormal distribution --------------------
1575
45728bfecb76 Random variable generators
Guido van Rossum <guido@python.org>
parents:
diff changeset
349
16242
3c5f09422b69 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 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
351 """Log normal distribution.
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings.
Raymond Hettinger <python@rcn.com>
parents: 23521
diff changeset
352
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings.
Raymond Hettinger <python@rcn.com>
parents: 23521
diff changeset
353 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
354 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
355 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
356
23531
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings.
Raymond Hettinger <python@rcn.com>
parents: 23521
diff changeset
357 """
16242
3c5f09422b69 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 return _exp(self.normalvariate(mu, sigma))
1575
45728bfecb76 Random variable generators
Guido van Rossum <guido@python.org>
parents:
diff changeset
359
16265
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics.
Tim Peters <tim.peters@gmail.com>
parents: 16243
diff changeset
360 ## -------------------- exponential distribution --------------------
1575
45728bfecb76 Random variable generators
Guido van Rossum <guido@python.org>
parents:
diff changeset
361
16242
3c5f09422b69 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 def expovariate(self, lambd):
23531
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings.
Raymond Hettinger <python@rcn.com>
parents: 23521
diff changeset
363 """Exponential distribution.
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings.
Raymond Hettinger <python@rcn.com>
parents: 23521
diff changeset
364
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings.
Raymond Hettinger <python@rcn.com>
parents: 23521
diff changeset
365 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
366 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
367 values range from 0 to positive infinity.
23536
0a4c92559a0b Whitespace normalized.
Raymond Hettinger <python@rcn.com>
parents: 23531
diff changeset
368
23531
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings.
Raymond Hettinger <python@rcn.com>
parents: 23521
diff changeset
369 """
16242
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the
Tim Peters <tim.peters@gmail.com>
parents: 15871
diff changeset
370 # 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
371 # ('lambda' is a Python reserved word)
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 random = self.random
15871
62aeefa01fdd Whitespace normalization.
Tim Peters <tim.peters@gmail.com>
parents: 14617
diff changeset
374 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
375 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
376 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
377 return -_log(u)/lambd
1575
45728bfecb76 Random variable generators
Guido van Rossum <guido@python.org>
parents:
diff changeset
378
16265
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics.
Tim Peters <tim.peters@gmail.com>
parents: 16243
diff changeset
379 ## -------------------- von Mises distribution --------------------
1575
45728bfecb76 Random variable generators
Guido van Rossum <guido@python.org>
parents:
diff changeset
380
16242
3c5f09422b69 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 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
382 """Circular data distribution.
23536
0a4c92559a0b Whitespace normalized.
Raymond Hettinger <python@rcn.com>
parents: 23531
diff changeset
383
23531
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings.
Raymond Hettinger <python@rcn.com>
parents: 23521
diff changeset
384 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
385 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
386 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
387 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
388
23531
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings.
Raymond Hettinger <python@rcn.com>
parents: 23521
diff changeset
389 """
16242
3c5f09422b69 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 # 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
391 # 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
392 # if kappa = 0 generate uniform random angle
1575
45728bfecb76 Random variable generators
Guido van Rossum <guido@python.org>
parents:
diff changeset
393
16242
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the
Tim Peters <tim.peters@gmail.com>
parents: 15871
diff changeset
394 # 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
395 # "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
396 # 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
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 # 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
399 # 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
400
16242
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the
Tim Peters <tim.peters@gmail.com>
parents: 15871
diff changeset
401 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
402 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
403 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
404
16242
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the
Tim Peters <tim.peters@gmail.com>
parents: 15871
diff changeset
405 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
406 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
407 r = (1.0 + b * b)/(2.0 * b)
1575
45728bfecb76 Random variable generators
Guido van Rossum <guido@python.org>
parents:
diff changeset
408
26266
42279f7d244d Improve comments. Clarify docs.
Raymond Hettinger <python@rcn.com>
parents: 26178
diff changeset
409 while True:
16242
3c5f09422b69 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 u1 = random()
1575
45728bfecb76 Random variable generators
Guido van Rossum <guido@python.org>
parents:
diff changeset
411
16242
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the
Tim Peters <tim.peters@gmail.com>
parents: 15871
diff changeset
412 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
413 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
414 c = kappa * (r - f)
1575
45728bfecb76 Random variable generators
Guido van Rossum <guido@python.org>
parents:
diff changeset
415
16242
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the
Tim Peters <tim.peters@gmail.com>
parents: 15871
diff changeset
416 u2 = random()
1575
45728bfecb76 Random variable generators
Guido van Rossum <guido@python.org>
parents:
diff changeset
417
16242
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the
Tim Peters <tim.peters@gmail.com>
parents: 15871
diff changeset
418 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
419 break
1575
45728bfecb76 Random variable generators
Guido van Rossum <guido@python.org>
parents:
diff changeset
420
16242
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the
Tim Peters <tim.peters@gmail.com>
parents: 15871
diff changeset
421 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
422 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
423 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
424 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
425 theta = (mu % TWOPI) - _acos(f)
1575
45728bfecb76 Random variable generators
Guido van Rossum <guido@python.org>
parents:
diff changeset
426
16242
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the
Tim Peters <tim.peters@gmail.com>
parents: 15871
diff changeset
427 return theta
1575
45728bfecb76 Random variable generators
Guido van Rossum <guido@python.org>
parents:
diff changeset
428
16265
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics.
Tim Peters <tim.peters@gmail.com>
parents: 16243
diff changeset
429 ## -------------------- gamma distribution --------------------
1575
45728bfecb76 Random variable generators
Guido van Rossum <guido@python.org>
parents:
diff changeset
430
16242
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the
Tim Peters <tim.peters@gmail.com>
parents: 15871
diff changeset
431 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
432 """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
433
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings.
Raymond Hettinger <python@rcn.com>
parents: 23521
diff changeset
434 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
435
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings.
Raymond Hettinger <python@rcn.com>
parents: 23521
diff changeset
436 """
23521
a90faa5f9417 Whitespace normalization.
Tim Peters <tim.peters@gmail.com>
parents: 23451
diff changeset
437
23447
08ccb0f3e2d4 Closes patch 529408 deprecating random.stdgamma().
Raymond Hettinger <python@rcn.com>
parents: 23442
diff changeset
438 # alpha > 0, beta > 0, mean is alpha*beta, variance is alpha*beta**2
23521
a90faa5f9417 Whitespace normalization.
Tim Peters <tim.peters@gmail.com>
parents: 23451
diff changeset
439
23451
273dd2508c57 Use spaces, not tabs for indents.
Guido van Rossum <guido@python.org>
parents: 23447
diff changeset
440 # 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
441 # of alpha > -1.0
273dd2508c57 Use spaces, not tabs for indents.
Guido van Rossum <guido@python.org>
parents: 23447
diff changeset
442 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
443 raise ValueError, 'gammavariate: alpha and beta must be > 0.0'
23521
a90faa5f9417 Whitespace normalization.
Tim Peters <tim.peters@gmail.com>
parents: 23451
diff changeset
444
16242
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the
Tim Peters <tim.peters@gmail.com>
parents: 15871
diff changeset
445 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
446 if alpha > 1.0:
1575
45728bfecb76 Random variable generators
Guido van Rossum <guido@python.org>
parents:
diff changeset
447
16242
3c5f09422b69 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 # 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
449 # 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
450 # Applied Statistics, (1977), 26, No. 1, p71-74
1575
45728bfecb76 Random variable generators
Guido van Rossum <guido@python.org>
parents:
diff changeset
451
23442
b15896053933 Closes SF bug 527139. Moved temp variables inside guard.
Raymond Hettinger <python@rcn.com>
parents: 23380
diff changeset
452 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
453 bbb = alpha - LOG4
b15896053933 Closes SF bug 527139. Moved temp variables inside guard.
Raymond Hettinger <python@rcn.com>
parents: 23380
diff changeset
454 ccc = alpha + ainv
23521
a90faa5f9417 Whitespace normalization.
Tim Peters <tim.peters@gmail.com>
parents: 23451
diff changeset
455
26266
42279f7d244d Improve comments. Clarify docs.
Raymond Hettinger <python@rcn.com>
parents: 26178
diff changeset
456 while True:
16242
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the
Tim Peters <tim.peters@gmail.com>
parents: 15871
diff changeset
457 u1 = random()
27085
90350b5d3397 Correct long standing bugs in the methods for random distributions.
Raymond Hettinger <python@rcn.com>
parents: 27080
diff changeset
458 if not 1e-7 < u1 < .9999999:
90350b5d3397 Correct long standing bugs in the methods for random distributions.
Raymond Hettinger <python@rcn.com>
parents: 27080
diff changeset
459 continue
90350b5d3397 Correct long standing bugs in the methods for random distributions.
Raymond Hettinger <python@rcn.com>
parents: 27080
diff changeset
460 u2 = 1.0 - random()
16242
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the
Tim Peters <tim.peters@gmail.com>
parents: 15871
diff changeset
461 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
462 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
463 z = u1*u1*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
464 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
465 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
466 return x * beta
1575
45728bfecb76 Random variable generators
Guido van Rossum <guido@python.org>
parents:
diff changeset
467
16242
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the
Tim Peters <tim.peters@gmail.com>
parents: 15871
diff changeset
468 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
469 # expovariate(1)
15871
62aeefa01fdd Whitespace normalization.
Tim Peters <tim.peters@gmail.com>
parents: 14617
diff changeset
470 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
471 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
472 u = random()
23447
08ccb0f3e2d4 Closes patch 529408 deprecating random.stdgamma().
Raymond Hettinger <python@rcn.com>
parents: 23442
diff changeset
473 return -_log(u) * beta
1575
45728bfecb76 Random variable generators
Guido van Rossum <guido@python.org>
parents:
diff changeset
474
16242
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the
Tim Peters <tim.peters@gmail.com>
parents: 15871
diff changeset
475 else: # alpha is between 0 and 1 (exclusive)
1575
45728bfecb76 Random variable generators
Guido van Rossum <guido@python.org>
parents:
diff changeset
476
16242
3c5f09422b69 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 # Uses ALGORITHM GS of Statistical Computing - Kennedy & Gentle
1575
45728bfecb76 Random variable generators
Guido van Rossum <guido@python.org>
parents:
diff changeset
478
26266
42279f7d244d Improve comments. Clarify docs.
Raymond Hettinger <python@rcn.com>
parents: 26178
diff changeset
479 while True:
16242
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the
Tim Peters <tim.peters@gmail.com>
parents: 15871
diff changeset
480 u = random()
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the
Tim Peters <tim.peters@gmail.com>
parents: 15871
diff changeset
481 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
482 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
483 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
484 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
485 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
486 # 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
487 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
488 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
489 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
490 ((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
491 break
23447
08ccb0f3e2d4 Closes patch 529408 deprecating random.stdgamma().
Raymond Hettinger <python@rcn.com>
parents: 23442
diff changeset
492 return x * beta
08ccb0f3e2d4 Closes patch 529408 deprecating random.stdgamma().
Raymond Hettinger <python@rcn.com>
parents: 23442
diff changeset
493
16265
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics.
Tim Peters <tim.peters@gmail.com>
parents: 16243
diff changeset
494 ## -------------------- 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
495
16242
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the
Tim Peters <tim.peters@gmail.com>
parents: 15871
diff changeset
496 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
497 """Gaussian distribution.
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings.
Raymond Hettinger <python@rcn.com>
parents: 23521
diff changeset
498
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings.
Raymond Hettinger <python@rcn.com>
parents: 23521
diff changeset
499 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
500 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
501
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings.
Raymond Hettinger <python@rcn.com>
parents: 23521
diff changeset
502 Not thread-safe without a lock around calls.
23536
0a4c92559a0b Whitespace normalized.
Raymond Hettinger <python@rcn.com>
parents: 23531
diff changeset
503
23531
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings.
Raymond Hettinger <python@rcn.com>
parents: 23521
diff changeset
504 """
1577
444e349f962f Use float constants directly; cosmetic changes; initialize largest
Guido van Rossum <guido@python.org>
parents: 1576
diff changeset
505
16242
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the
Tim Peters <tim.peters@gmail.com>
parents: 15871
diff changeset
506 # 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
507 # 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
508 #
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the
Tim Peters <tim.peters@gmail.com>
parents: 15871
diff changeset
509 # cos(2*pi*x)*sqrt(-2*log(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
510 # sin(2*pi*x)*sqrt(-2*log(1-y))
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the
Tim Peters <tim.peters@gmail.com>
parents: 15871
diff changeset
511 #
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the
Tim Peters <tim.peters@gmail.com>
parents: 15871
diff changeset
512 # 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
513 # (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
514 # (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
515 # (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
516
16242
3c5f09422b69 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 # 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
518 # 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
519 # 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
520 # 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
521 # 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
522 # lock here.)
1577
444e349f962f Use float constants directly; cosmetic changes; initialize largest
Guido van Rossum <guido@python.org>
parents: 1576
diff changeset
523
16242
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the
Tim Peters <tim.peters@gmail.com>
parents: 15871
diff changeset
524 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
525 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
526 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
527 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
528 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
529 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
530 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
531 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
532
16242
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the
Tim Peters <tim.peters@gmail.com>
parents: 15871
diff changeset
533 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
534
16265
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics.
Tim Peters <tim.peters@gmail.com>
parents: 16243
diff changeset
535 ## -------------------- beta --------------------
16271
7ef2382f6123 SF bug 130030: Claim of bad betavariate algorithm.
Tim Peters <tim.peters@gmail.com>
parents: 16265
diff changeset
536 ## See
7ef2382f6123 SF bug 130030: Claim of bad betavariate algorithm.
Tim Peters <tim.peters@gmail.com>
parents: 16265
diff changeset
537 ## 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
538 ## 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
539 ##
7ef2382f6123 SF bug 130030: Claim of bad betavariate algorithm.
Tim Peters <tim.peters@gmail.com>
parents: 16265
diff changeset
540 ## def betavariate(self, alpha, beta):
7ef2382f6123 SF bug 130030: Claim of bad betavariate algorithm.
Tim Peters <tim.peters@gmail.com>
parents: 16265
diff changeset
541 ## # 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
542 ##
7ef2382f6123 SF bug 130030: Claim of bad betavariate algorithm.
Tim Peters <tim.peters@gmail.com>
parents: 16265
diff changeset
543 ## y = self.expovariate(alpha)
7ef2382f6123 SF bug 130030: Claim of bad betavariate algorithm.
Tim Peters <tim.peters@gmail.com>
parents: 16265
diff changeset
544 ## 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
545 ## return z/(y+z)
7ef2382f6123 SF bug 130030: Claim of bad betavariate algorithm.
Tim Peters <tim.peters@gmail.com>
parents: 16265
diff changeset
546 ##
7ef2382f6123 SF bug 130030: Claim of bad betavariate algorithm.
Tim Peters <tim.peters@gmail.com>
parents: 16265
diff changeset
547 ## 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
548
16242
3c5f09422b69 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 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
550 """Beta distribution.
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings.
Raymond Hettinger <python@rcn.com>
parents: 23521
diff changeset
551
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings.
Raymond Hettinger <python@rcn.com>
parents: 23521
diff changeset
552 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
553 Returned values range between 0 and 1.
23536
0a4c92559a0b Whitespace normalized.
Raymond Hettinger <python@rcn.com>
parents: 23531
diff changeset
554
23531
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings.
Raymond Hettinger <python@rcn.com>
parents: 23521
diff changeset
555 """
23536
0a4c92559a0b Whitespace normalized.
Raymond Hettinger <python@rcn.com>
parents: 23531
diff changeset
556
16271
7ef2382f6123 SF bug 130030: Claim of bad betavariate algorithm.
Tim Peters <tim.peters@gmail.com>
parents: 16265
diff changeset
557 # 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
558 # 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
559 y = self.gammavariate(alpha, 1.)
7ef2382f6123 SF bug 130030: Claim of bad betavariate algorithm.
Tim Peters <tim.peters@gmail.com>
parents: 16265
diff changeset
560 if y == 0:
7ef2382f6123 SF bug 130030: Claim of bad betavariate algorithm.
Tim Peters <tim.peters@gmail.com>
parents: 16265
diff changeset
561 return 0.0
7ef2382f6123 SF bug 130030: Claim of bad betavariate algorithm.
Tim Peters <tim.peters@gmail.com>
parents: 16265
diff changeset
562 else:
7ef2382f6123 SF bug 130030: Claim of bad betavariate algorithm.
Tim Peters <tim.peters@gmail.com>
parents: 16265
diff changeset
563 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
564
16265
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics.
Tim Peters <tim.peters@gmail.com>
parents: 16243
diff changeset
565 ## -------------------- Pareto --------------------
6698
b73eb4e6face Added Pareto and Weibull distributions, courtesy Jeremy Hylton.
Guido van Rossum <guido@python.org>
parents: 1618
diff changeset
566
16242
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the
Tim Peters <tim.peters@gmail.com>
parents: 15871
diff changeset
567 def paretovariate(self, alpha):
23531
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings.
Raymond Hettinger <python@rcn.com>
parents: 23521
diff changeset
568 """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
569 # Jain, pg. 495
6698
b73eb4e6face Added Pareto and Weibull distributions, courtesy Jeremy Hylton.
Guido van Rossum <guido@python.org>
parents: 1618
diff changeset
570
27085
90350b5d3397 Correct long standing bugs in the methods for random distributions.
Raymond Hettinger <python@rcn.com>
parents: 27080
diff changeset
571 u = 1.0 - self.random()
16242
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the
Tim Peters <tim.peters@gmail.com>
parents: 15871
diff changeset
572 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
573
16265
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics.
Tim Peters <tim.peters@gmail.com>
parents: 16243
diff changeset
574 ## -------------------- Weibull --------------------
6698
b73eb4e6face Added Pareto and Weibull distributions, courtesy Jeremy Hylton.
Guido van Rossum <guido@python.org>
parents: 1618
diff changeset
575
16242
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the
Tim Peters <tim.peters@gmail.com>
parents: 15871
diff changeset
576 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
577 """Weibull distribution.
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings.
Raymond Hettinger <python@rcn.com>
parents: 23521
diff changeset
578
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings.
Raymond Hettinger <python@rcn.com>
parents: 23521
diff changeset
579 alpha is the scale parameter and beta is the shape parameter.
23536
0a4c92559a0b Whitespace normalized.
Raymond Hettinger <python@rcn.com>
parents: 23531
diff changeset
580
23531
a98e93eafef7 Deprecated Random.cunifvariate clearing bug 506647. Also, added docstrings.
Raymond Hettinger <python@rcn.com>
parents: 23521
diff changeset
581 """
16242
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the
Tim Peters <tim.peters@gmail.com>
parents: 15871
diff changeset
582 # 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
583
27085
90350b5d3397 Correct long standing bugs in the methods for random distributions.
Raymond Hettinger <python@rcn.com>
parents: 27080
diff changeset
584 u = 1.0 - self.random()
16242
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the
Tim Peters <tim.peters@gmail.com>
parents: 15871
diff changeset
585 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
586
26829
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
587 ## -------------------- Wichmann-Hill -------------------
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
588
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
589 class WichmannHill(Random):
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
590
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
591 VERSION = 1 # used by getstate/setstate
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
592
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
593 def seed(self, a=None):
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
594 """Initialize internal state from hashable object.
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
595
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
596 None or no argument seeds from current time.
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
597
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
598 If a is not None or an int or long, hash(a) is used instead.
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
599
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
600 If a is an int or long, a is used directly. Distinct values between
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
601 0 and 27814431486575L inclusive are guaranteed to yield distinct
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
602 internal states (this guarantee is specific to the default
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
603 Wichmann-Hill generator).
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
604 """
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
605
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
606 if a is None:
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
607 # Initialize from current time
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
608 import time
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
609 a = long(time.time() * 256)
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
610
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
611 if not isinstance(a, (int, long)):
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
612 a = hash(a)
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
613
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
614 a, x = divmod(a, 30268)
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
615 a, y = divmod(a, 30306)
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
616 a, z = divmod(a, 30322)
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
617 self._seed = int(x)+1, int(y)+1, int(z)+1
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
618
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
619 self.gauss_next = None
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
620
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
621 def random(self):
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
622 """Get the next random number in the range [0.0, 1.0)."""
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
623
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
624 # Wichman-Hill random number generator.
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
625 #
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
626 # Wichmann, B. A. & Hill, I. D. (1982)
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
627 # Algorithm AS 183:
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
628 # An efficient and portable pseudo-random number generator
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
629 # Applied Statistics 31 (1982) 188-190
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
630 #
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
631 # see also:
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
632 # Correction to Algorithm AS 183
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
633 # Applied Statistics 33 (1984) 123
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
634 #
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
635 # McLeod, A. I. (1985)
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
636 # A remark on Algorithm AS 183
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
637 # Applied Statistics 34 (1985),198-200
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
638
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
639 # This part is thread-unsafe:
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
640 # BEGIN CRITICAL SECTION
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
641 x, y, z = self._seed
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
642 x = (171 * x) % 30269
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
643 y = (172 * y) % 30307
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
644 z = (170 * z) % 30323
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
645 self._seed = x, y, z
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
646 # END CRITICAL SECTION
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
647
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
648 # Note: on a platform using IEEE-754 double arithmetic, this can
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
649 # never return 0.0 (asserted by Tim; proof too long for a comment).
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
650 return (x/30269.0 + y/30307.0 + z/30323.0) % 1.0
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
651
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
652 def getstate(self):
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
653 """Return internal state; can be passed to setstate() later."""
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
654 return self.VERSION, self._seed, self.gauss_next
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
655
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
656 def setstate(self, state):
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
657 """Restore internal state from object returned by getstate()."""
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
658 version = state[0]
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
659 if version == 1:
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
660 version, self._seed, self.gauss_next = state
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
661 else:
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
662 raise ValueError("state with version %s passed to "
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
663 "Random.setstate() of version %s" %
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
664 (version, self.VERSION))
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
665
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
666 def jumpahead(self, n):
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
667 """Act as if n calls to random() were made, but quickly.
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
668
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
669 n is an int, greater than or equal to 0.
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
670
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
671 Example use: If you have 2 threads and know that each will
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
672 consume no more than a million random numbers, create two Random
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
673 objects r1 and r2, then do
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
674 r2.setstate(r1.getstate())
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
675 r2.jumpahead(1000000)
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
676 Then r1 and r2 will use guaranteed-disjoint segments of the full
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
677 period.
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
678 """
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
679
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
680 if not n >= 0:
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
681 raise ValueError("n must be >= 0")
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
682 x, y, z = self._seed
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
683 x = int(x * pow(171, n, 30269)) % 30269
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
684 y = int(y * pow(172, n, 30307)) % 30307
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
685 z = int(z * pow(170, n, 30323)) % 30323
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
686 self._seed = x, y, z
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
687
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
688 def __whseed(self, x=0, y=0, z=0):
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
689 """Set the Wichmann-Hill seed from (x, y, z).
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
690
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
691 These must be integers in the range [0, 256).
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
692 """
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
693
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
694 if not type(x) == type(y) == type(z) == int:
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
695 raise TypeError('seeds must be integers')
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
696 if not (0 <= x < 256 and 0 <= y < 256 and 0 <= z < 256):
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
697 raise ValueError('seeds must be in range(0, 256)')
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
698 if 0 == x == y == z:
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
699 # Initialize from current time
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
700 import time
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
701 t = long(time.time() * 256)
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
702 t = int((t&0xffffff) ^ (t>>24))
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
703 t, x = divmod(t, 256)
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
704 t, y = divmod(t, 256)
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
705 t, z = divmod(t, 256)
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
706 # Zero is a poor seed, so substitute 1
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
707 self._seed = (x or 1, y or 1, z or 1)
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
708
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
709 self.gauss_next = None
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
710
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
711 def whseed(self, a=None):
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
712 """Seed from hashable object's hash code.
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
713
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
714 None or no argument seeds from current time. It is not guaranteed
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
715 that objects with distinct hash codes lead to distinct internal
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
716 states.
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
717
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
718 This is obsolete, provided for compatibility with the seed routine
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
719 used prior to Python 2.1. Use the .seed() method instead.
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
720 """
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
721
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
722 if a is None:
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
723 self.__whseed()
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
724 return
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
725 a = hash(a)
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
726 a, x = divmod(a, 256)
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
727 a, y = divmod(a, 256)
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
728 a, z = divmod(a, 256)
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
729 x = (x + a) % 256 or 1
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
730 y = (y + a) % 256 or 1
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
731 z = (z + a) % 256 or 1
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
732 self.__whseed(x, y, z)
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
733
16265
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics.
Tim Peters <tim.peters@gmail.com>
parents: 16243
diff changeset
734 ## -------------------- test program --------------------
1575
45728bfecb76 Random variable generators
Guido van Rossum <guido@python.org>
parents:
diff changeset
735
30243
53a322c6de52 Eliminate unnecessary eval() in tests
Raymond Hettinger <python@rcn.com>
parents: 30114
diff changeset
736 def _test_generator(n, func, args):
15871
62aeefa01fdd Whitespace normalization.
Tim Peters <tim.peters@gmail.com>
parents: 14617
diff changeset
737 import time
30243
53a322c6de52 Eliminate unnecessary eval() in tests
Raymond Hettinger <python@rcn.com>
parents: 30114
diff changeset
738 print n, 'times', func.__name__
29250
34609fa35b11 'sum' is no longer a good variable name. Use 'total' instead.
Raymond Hettinger <python@rcn.com>
parents: 27279
diff changeset
739 total = 0.0
15871
62aeefa01fdd Whitespace normalization.
Tim Peters <tim.peters@gmail.com>
parents: 14617
diff changeset
740 sqsum = 0.0
62aeefa01fdd Whitespace normalization.
Tim Peters <tim.peters@gmail.com>
parents: 14617
diff changeset
741 smallest = 1e10
62aeefa01fdd Whitespace normalization.
Tim Peters <tim.peters@gmail.com>
parents: 14617
diff changeset
742 largest = -1e10
62aeefa01fdd Whitespace normalization.
Tim Peters <tim.peters@gmail.com>
parents: 14617
diff changeset
743 t0 = time.time()
62aeefa01fdd Whitespace normalization.
Tim Peters <tim.peters@gmail.com>
parents: 14617
diff changeset
744 for i in range(n):
30243
53a322c6de52 Eliminate unnecessary eval() in tests
Raymond Hettinger <python@rcn.com>
parents: 30114
diff changeset
745 x = func(*args)
29250
34609fa35b11 'sum' is no longer a good variable name. Use 'total' instead.
Raymond Hettinger <python@rcn.com>
parents: 27279
diff changeset
746 total += x
15871
62aeefa01fdd Whitespace normalization.
Tim Peters <tim.peters@gmail.com>
parents: 14617
diff changeset
747 sqsum = sqsum + x*x
62aeefa01fdd Whitespace normalization.
Tim Peters <tim.peters@gmail.com>
parents: 14617
diff changeset
748 smallest = min(x, smallest)
62aeefa01fdd Whitespace normalization.
Tim Peters <tim.peters@gmail.com>
parents: 14617
diff changeset
749 largest = max(x, largest)
62aeefa01fdd Whitespace normalization.
Tim Peters <tim.peters@gmail.com>
parents: 14617
diff changeset
750 t1 = time.time()
62aeefa01fdd Whitespace normalization.
Tim Peters <tim.peters@gmail.com>
parents: 14617
diff changeset
751 print round(t1-t0, 3), 'sec,',
29250
34609fa35b11 'sum' is no longer a good variable name. Use 'total' instead.
Raymond Hettinger <python@rcn.com>
parents: 27279
diff changeset
752 avg = total/n
16242
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the
Tim Peters <tim.peters@gmail.com>
parents: 15871
diff changeset
753 stddev = _sqrt(sqsum/n - avg*avg)
15871
62aeefa01fdd Whitespace normalization.
Tim Peters <tim.peters@gmail.com>
parents: 14617
diff changeset
754 print 'avg %g, stddev %g, min %g, max %g' % \
62aeefa01fdd Whitespace normalization.
Tim Peters <tim.peters@gmail.com>
parents: 14617
diff changeset
755 (avg, stddev, smallest, largest)
1575
45728bfecb76 Random variable generators
Guido van Rossum <guido@python.org>
parents:
diff changeset
756
26155
8ceb455f5541 SF patch 629637: Add sample(population, k) method to the random module.
Raymond Hettinger <python@rcn.com>
parents: 24861
diff changeset
757
8ceb455f5541 SF patch 629637: Add sample(population, k) method to the random module.
Raymond Hettinger <python@rcn.com>
parents: 24861
diff changeset
758 def _test(N=2000):
30243
53a322c6de52 Eliminate unnecessary eval() in tests
Raymond Hettinger <python@rcn.com>
parents: 30114
diff changeset
759 _test_generator(N, random, ())
53a322c6de52 Eliminate unnecessary eval() in tests
Raymond Hettinger <python@rcn.com>
parents: 30114
diff changeset
760 _test_generator(N, normalvariate, (0.0, 1.0))
53a322c6de52 Eliminate unnecessary eval() in tests
Raymond Hettinger <python@rcn.com>
parents: 30114
diff changeset
761 _test_generator(N, lognormvariate, (0.0, 1.0))
53a322c6de52 Eliminate unnecessary eval() in tests
Raymond Hettinger <python@rcn.com>
parents: 30114
diff changeset
762 _test_generator(N, vonmisesvariate, (0.0, 1.0))
53a322c6de52 Eliminate unnecessary eval() in tests
Raymond Hettinger <python@rcn.com>
parents: 30114
diff changeset
763 _test_generator(N, gammavariate, (0.01, 1.0))
53a322c6de52 Eliminate unnecessary eval() in tests
Raymond Hettinger <python@rcn.com>
parents: 30114
diff changeset
764 _test_generator(N, gammavariate, (0.1, 1.0))
53a322c6de52 Eliminate unnecessary eval() in tests
Raymond Hettinger <python@rcn.com>
parents: 30114
diff changeset
765 _test_generator(N, gammavariate, (0.1, 2.0))
53a322c6de52 Eliminate unnecessary eval() in tests
Raymond Hettinger <python@rcn.com>
parents: 30114
diff changeset
766 _test_generator(N, gammavariate, (0.5, 1.0))
53a322c6de52 Eliminate unnecessary eval() in tests
Raymond Hettinger <python@rcn.com>
parents: 30114
diff changeset
767 _test_generator(N, gammavariate, (0.9, 1.0))
53a322c6de52 Eliminate unnecessary eval() in tests
Raymond Hettinger <python@rcn.com>
parents: 30114
diff changeset
768 _test_generator(N, gammavariate, (1.0, 1.0))
53a322c6de52 Eliminate unnecessary eval() in tests
Raymond Hettinger <python@rcn.com>
parents: 30114
diff changeset
769 _test_generator(N, gammavariate, (2.0, 1.0))
53a322c6de52 Eliminate unnecessary eval() in tests
Raymond Hettinger <python@rcn.com>
parents: 30114
diff changeset
770 _test_generator(N, gammavariate, (20.0, 1.0))
53a322c6de52 Eliminate unnecessary eval() in tests
Raymond Hettinger <python@rcn.com>
parents: 30114
diff changeset
771 _test_generator(N, gammavariate, (200.0, 1.0))
53a322c6de52 Eliminate unnecessary eval() in tests
Raymond Hettinger <python@rcn.com>
parents: 30114
diff changeset
772 _test_generator(N, gauss, (0.0, 1.0))
53a322c6de52 Eliminate unnecessary eval() in tests
Raymond Hettinger <python@rcn.com>
parents: 30114
diff changeset
773 _test_generator(N, betavariate, (3.0, 3.0))
16265
d614b6e9fb4e Cosmetic changes after some sleep; no change in semantics.
Tim Peters <tim.peters@gmail.com>
parents: 16243
diff changeset
774
16292
0501c2a10315 New comment block to Clarify a subtlety.
Tim Peters <tim.peters@gmail.com>
parents: 16272
diff changeset
775 # Create one instance, seeded from current time, and export its methods
26829
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
776 # as module-level functions. The functions share state across all uses
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
777 #(both in the user's code and in the Python libraries), but that's fine
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
778 # for most programs and is easier for the casual user than making them
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
779 # instantiate their own Random() instance.
f64c96922708 SF patch 658251: Install a C implementation of the Mersenne Twister as the
Raymond Hettinger <python@rcn.com>
parents: 26564
diff changeset
780
16242
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the
Tim Peters <tim.peters@gmail.com>
parents: 15871
diff changeset
781 _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
782 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
783 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
784 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
785 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
786 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
787 randrange = _inst.randrange
26155
8ceb455f5541 SF patch 629637: Add sample(population, k) method to the random module.
Raymond Hettinger <python@rcn.com>
parents: 24861
diff changeset
788 sample = _inst.sample
16242
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the
Tim Peters <tim.peters@gmail.com>
parents: 15871
diff changeset
789 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
790 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
791 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
792 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
793 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
794 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
795 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
796 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
797 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
798 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
799 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
800 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
801 jumpahead = _inst.jumpahead
30649
8841d34a2c37 SF bug #812202: randint is always even
Raymond Hettinger <python@rcn.com>
parents: 30346
diff changeset
802 getrandbits = _inst.getrandbits
16242
3c5f09422b69 Reworked random.py so that it no longer depends on, and offers all the
Tim Peters <tim.peters@gmail.com>
parents: 15871
diff changeset
803
1575
45728bfecb76 Random variable generators
Guido van Rossum <guido@python.org>
parents:
diff changeset
804 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
805 _test()