Guido van Rossum | e7b146f | 2000-02-04 15:28:42 +0000 | [diff] [blame] | 1 | """Random variable generators. |
Guido van Rossum | ff03b1a | 1994-03-09 12:55:02 +0000 | [diff] [blame] | 2 | |
Tim Peters | d7b5e88 | 2001-01-25 03:36:26 +0000 | [diff] [blame] | 3 | integers |
| 4 | -------- |
| 5 | uniform within range |
| 6 | |
| 7 | sequences |
| 8 | --------- |
| 9 | pick random element |
Raymond Hettinger | f24eb35 | 2002-11-12 17:41:57 +0000 | [diff] [blame] | 10 | pick random sample |
Raymond Hettinger | e8f1e00 | 2016-09-06 17:15:29 -0700 | [diff] [blame] | 11 | pick weighted random sample |
Tim Peters | d7b5e88 | 2001-01-25 03:36:26 +0000 | [diff] [blame] | 12 | generate random permutation |
| 13 | |
Guido van Rossum | e7b146f | 2000-02-04 15:28:42 +0000 | [diff] [blame] | 14 | distributions on the real line: |
| 15 | ------------------------------ |
Tim Peters | d7b5e88 | 2001-01-25 03:36:26 +0000 | [diff] [blame] | 16 | uniform |
Christian Heimes | fe337bf | 2008-03-23 21:54:12 +0000 | [diff] [blame] | 17 | triangular |
Guido van Rossum | e7b146f | 2000-02-04 15:28:42 +0000 | [diff] [blame] | 18 | normal (Gaussian) |
| 19 | lognormal |
| 20 | negative exponential |
| 21 | gamma |
| 22 | beta |
Raymond Hettinger | 40f6217 | 2002-12-29 23:03:38 +0000 | [diff] [blame] | 23 | pareto |
| 24 | Weibull |
Guido van Rossum | ff03b1a | 1994-03-09 12:55:02 +0000 | [diff] [blame] | 25 | |
Guido van Rossum | e7b146f | 2000-02-04 15:28:42 +0000 | [diff] [blame] | 26 | distributions on the circle (angles 0 to 2pi) |
| 27 | --------------------------------------------- |
| 28 | circular uniform |
| 29 | von Mises |
| 30 | |
Raymond Hettinger | 40f6217 | 2002-12-29 23:03:38 +0000 | [diff] [blame] | 31 | General notes on the underlying Mersenne Twister core generator: |
Guido van Rossum | e7b146f | 2000-02-04 15:28:42 +0000 | [diff] [blame] | 32 | |
Raymond Hettinger | 40f6217 | 2002-12-29 23:03:38 +0000 | [diff] [blame] | 33 | * The period is 2**19937-1. |
Thomas Wouters | 0e3f591 | 2006-08-11 14:57:12 +0000 | [diff] [blame] | 34 | * It is one of the most extensively tested generators in existence. |
Thomas Wouters | 0e3f591 | 2006-08-11 14:57:12 +0000 | [diff] [blame] | 35 | * The random() method is implemented in C, executes in a single Python step, |
| 36 | and is, therefore, threadsafe. |
Tim Peters | e360d95 | 2001-01-26 10:00:39 +0000 | [diff] [blame] | 37 | |
Guido van Rossum | e7b146f | 2000-02-04 15:28:42 +0000 | [diff] [blame] | 38 | """ |
Guido van Rossum | d03e119 | 1998-05-29 17:51:31 +0000 | [diff] [blame] | 39 | |
Raymond Hettinger | 2f726e9 | 2003-10-05 09:09:15 +0000 | [diff] [blame] | 40 | from warnings import warn as _warn |
Raymond Hettinger | 91e27c2 | 2005-08-19 01:36:35 +0000 | [diff] [blame] | 41 | from math import log as _log, exp as _exp, pi as _pi, e as _e, ceil as _ceil |
Tim Peters | d7b5e88 | 2001-01-25 03:36:26 +0000 | [diff] [blame] | 42 | from math import sqrt as _sqrt, acos as _acos, cos as _cos, sin as _sin |
Raymond Hettinger | c1c43ca | 2004-09-05 00:00:42 +0000 | [diff] [blame] | 43 | from os import urandom as _urandom |
Christian Heimes | f1dc3ee | 2013-10-13 02:04:20 +0200 | [diff] [blame] | 44 | from _collections_abc import Set as _Set, Sequence as _Sequence |
Raymond Hettinger | 3fcf002 | 2010-12-08 01:13:53 +0000 | [diff] [blame] | 45 | from hashlib import sha512 as _sha512 |
Raymond Hettinger | e8f1e00 | 2016-09-06 17:15:29 -0700 | [diff] [blame] | 46 | import itertools as _itertools |
| 47 | import bisect as _bisect |
Antoine Pitrou | 346cbd3 | 2017-05-27 17:50:54 +0200 | [diff] [blame] | 48 | import os as _os |
Guido van Rossum | ff03b1a | 1994-03-09 12:55:02 +0000 | [diff] [blame] | 49 | |
Raymond Hettinger | f24eb35 | 2002-11-12 17:41:57 +0000 | [diff] [blame] | 50 | __all__ = ["Random","seed","random","uniform","randint","choice","sample", |
Skip Montanaro | 0de6580 | 2001-02-15 22:15:14 +0000 | [diff] [blame] | 51 | "randrange","shuffle","normalvariate","lognormvariate", |
Christian Heimes | fe337bf | 2008-03-23 21:54:12 +0000 | [diff] [blame] | 52 | "expovariate","vonmisesvariate","gammavariate","triangular", |
Raymond Hettinger | f8a52d3 | 2003-08-05 12:23:19 +0000 | [diff] [blame] | 53 | "gauss","betavariate","paretovariate","weibullvariate", |
Raymond Hettinger | 28aa4a0 | 2016-09-07 00:08:44 -0700 | [diff] [blame] | 54 | "getstate","setstate", "getrandbits", "choices", |
Raymond Hettinger | 23f1241 | 2004-09-13 22:23:21 +0000 | [diff] [blame] | 55 | "SystemRandom"] |
Tim Peters | d7b5e88 | 2001-01-25 03:36:26 +0000 | [diff] [blame] | 56 | |
| 57 | NV_MAGICCONST = 4 * _exp(-0.5)/_sqrt(2.0) |
Tim Peters | d7b5e88 | 2001-01-25 03:36:26 +0000 | [diff] [blame] | 58 | TWOPI = 2.0*_pi |
Tim Peters | d7b5e88 | 2001-01-25 03:36:26 +0000 | [diff] [blame] | 59 | LOG4 = _log(4.0) |
Tim Peters | d7b5e88 | 2001-01-25 03:36:26 +0000 | [diff] [blame] | 60 | SG_MAGICCONST = 1.0 + _log(4.5) |
Raymond Hettinger | 2f726e9 | 2003-10-05 09:09:15 +0000 | [diff] [blame] | 61 | BPF = 53 # Number of bits in a float |
Tim Peters | 7c2a85b | 2004-08-31 02:19:55 +0000 | [diff] [blame] | 62 | RECIP_BPF = 2**-BPF |
Tim Peters | d7b5e88 | 2001-01-25 03:36:26 +0000 | [diff] [blame] | 63 | |
Raymond Hettinger | 356a459 | 2004-08-30 06:14:31 +0000 | [diff] [blame] | 64 | |
Tim Peters | d7b5e88 | 2001-01-25 03:36:26 +0000 | [diff] [blame] | 65 | # Translated by Guido van Rossum from C source provided by |
Raymond Hettinger | 40f6217 | 2002-12-29 23:03:38 +0000 | [diff] [blame] | 66 | # Adrian Baddeley. Adapted by Raymond Hettinger for use with |
Raymond Hettinger | 3fa19d7 | 2004-08-31 01:05:15 +0000 | [diff] [blame] | 67 | # the Mersenne Twister and os.urandom() core generators. |
Tim Peters | d7b5e88 | 2001-01-25 03:36:26 +0000 | [diff] [blame] | 68 | |
Raymond Hettinger | 145a4a0 | 2003-01-07 10:25:55 +0000 | [diff] [blame] | 69 | import _random |
Raymond Hettinger | 40f6217 | 2002-12-29 23:03:38 +0000 | [diff] [blame] | 70 | |
Raymond Hettinger | 145a4a0 | 2003-01-07 10:25:55 +0000 | [diff] [blame] | 71 | class Random(_random.Random): |
Raymond Hettinger | c32f033 | 2002-05-23 19:44:49 +0000 | [diff] [blame] | 72 | """Random number generator base class used by bound module functions. |
| 73 | |
| 74 | Used to instantiate instances of Random to get generators that don't |
Raymond Hettinger | 28de64f | 2008-01-13 23:40:30 +0000 | [diff] [blame] | 75 | share state. |
Raymond Hettinger | c32f033 | 2002-05-23 19:44:49 +0000 | [diff] [blame] | 76 | |
| 77 | Class Random can also be subclassed if you want to use a different basic |
| 78 | generator of your own devising: in that case, override the following |
Raymond Hettinger | 28de64f | 2008-01-13 23:40:30 +0000 | [diff] [blame] | 79 | methods: random(), seed(), getstate(), and setstate(). |
Benjamin Peterson | d18de0e | 2008-07-31 20:21:46 +0000 | [diff] [blame] | 80 | Optionally, implement a getrandbits() method so that randrange() |
Raymond Hettinger | 2f726e9 | 2003-10-05 09:09:15 +0000 | [diff] [blame] | 81 | can cover arbitrarily large ranges. |
Raymond Hettinger | ef4d4bd | 2002-05-23 23:58:17 +0000 | [diff] [blame] | 82 | |
Raymond Hettinger | c32f033 | 2002-05-23 19:44:49 +0000 | [diff] [blame] | 83 | """ |
Tim Peters | d7b5e88 | 2001-01-25 03:36:26 +0000 | [diff] [blame] | 84 | |
Christian Heimes | cbf3b5c | 2007-12-03 21:02:03 +0000 | [diff] [blame] | 85 | VERSION = 3 # used by getstate/setstate |
Tim Peters | d7b5e88 | 2001-01-25 03:36:26 +0000 | [diff] [blame] | 86 | |
| 87 | def __init__(self, x=None): |
| 88 | """Initialize an instance. |
| 89 | |
| 90 | Optional argument x controls seeding, as for Random.seed(). |
| 91 | """ |
| 92 | |
| 93 | self.seed(x) |
Raymond Hettinger | 40f6217 | 2002-12-29 23:03:38 +0000 | [diff] [blame] | 94 | self.gauss_next = None |
Tim Peters | d7b5e88 | 2001-01-25 03:36:26 +0000 | [diff] [blame] | 95 | |
Wolfgang Maier | ba3a87a | 2018-04-17 17:16:17 +0200 | [diff] [blame] | 96 | def __init_subclass__(cls, **kwargs): |
| 97 | """Control how subclasses generate random integers. |
| 98 | |
| 99 | The algorithm a subclass can use depends on the random() and/or |
| 100 | getrandbits() implementation available to it and determines |
| 101 | whether it can generate random integers from arbitrarily large |
| 102 | ranges. |
| 103 | """ |
| 104 | |
Serhiy Storchaka | ec1622d | 2018-05-08 15:45:15 +0300 | [diff] [blame] | 105 | for c in cls.__mro__: |
| 106 | if '_randbelow' in c.__dict__: |
| 107 | # just inherit it |
| 108 | break |
| 109 | if 'getrandbits' in c.__dict__: |
| 110 | cls._randbelow = cls._randbelow_with_getrandbits |
| 111 | break |
| 112 | if 'random' in c.__dict__: |
| 113 | cls._randbelow = cls._randbelow_without_getrandbits |
| 114 | break |
Wolfgang Maier | ba3a87a | 2018-04-17 17:16:17 +0200 | [diff] [blame] | 115 | |
Raymond Hettinger | f763a72 | 2010-09-07 00:38:15 +0000 | [diff] [blame] | 116 | def seed(self, a=None, version=2): |
Tim Peters | 0de88fc | 2001-02-01 04:59:18 +0000 | [diff] [blame] | 117 | """Initialize internal state from hashable object. |
Tim Peters | d7b5e88 | 2001-01-25 03:36:26 +0000 | [diff] [blame] | 118 | |
Raymond Hettinger | 23f1241 | 2004-09-13 22:23:21 +0000 | [diff] [blame] | 119 | None or no argument seeds from current time or from an operating |
| 120 | system specific randomness source if available. |
Tim Peters | 0de88fc | 2001-02-01 04:59:18 +0000 | [diff] [blame] | 121 | |
Raymond Hettinger | 183cd1f | 2010-09-08 18:48:21 +0000 | [diff] [blame] | 122 | If *a* is an int, all bits are used. |
Raymond Hettinger | f763a72 | 2010-09-07 00:38:15 +0000 | [diff] [blame] | 123 | |
Raymond Hettinger | 16eb827 | 2016-09-04 11:17:28 -0700 | [diff] [blame] | 124 | For version 2 (the default), all of the bits are used if *a* is a str, |
| 125 | bytes, or bytearray. For version 1 (provided for reproducing random |
| 126 | sequences from older versions of Python), the algorithm for str and |
| 127 | bytes generates a narrower range of seeds. |
| 128 | |
Tim Peters | d7b5e88 | 2001-01-25 03:36:26 +0000 | [diff] [blame] | 129 | """ |
| 130 | |
Raymond Hettinger | c7bab7c | 2016-08-31 15:01:08 -0700 | [diff] [blame] | 131 | if version == 1 and isinstance(a, (str, bytes)): |
Raymond Hettinger | 132a7d7 | 2017-09-17 09:04:30 -0700 | [diff] [blame] | 132 | a = a.decode('latin-1') if isinstance(a, bytes) else a |
Raymond Hettinger | c7bab7c | 2016-08-31 15:01:08 -0700 | [diff] [blame] | 133 | x = ord(a[0]) << 7 if a else 0 |
Raymond Hettinger | 132a7d7 | 2017-09-17 09:04:30 -0700 | [diff] [blame] | 134 | for c in map(ord, a): |
| 135 | x = ((1000003 * x) ^ c) & 0xFFFFFFFFFFFFFFFF |
Raymond Hettinger | c7bab7c | 2016-08-31 15:01:08 -0700 | [diff] [blame] | 136 | x ^= len(a) |
| 137 | a = -2 if x == -1 else x |
| 138 | |
Raymond Hettinger | 2f9cc7a | 2016-08-31 23:00:32 -0700 | [diff] [blame] | 139 | if version == 2 and isinstance(a, (str, bytes, bytearray)): |
| 140 | if isinstance(a, str): |
| 141 | a = a.encode() |
| 142 | a += _sha512(a).digest() |
| 143 | a = int.from_bytes(a, 'big') |
Raymond Hettinger | f763a72 | 2010-09-07 00:38:15 +0000 | [diff] [blame] | 144 | |
Guido van Rossum | cd16bf6 | 2007-06-13 18:07:49 +0000 | [diff] [blame] | 145 | super().seed(a) |
Tim Peters | 46c04e1 | 2002-05-05 20:40:00 +0000 | [diff] [blame] | 146 | self.gauss_next = None |
| 147 | |
Tim Peters | cd80410 | 2001-01-25 20:25:57 +0000 | [diff] [blame] | 148 | def getstate(self): |
| 149 | """Return internal state; can be passed to setstate() later.""" |
Guido van Rossum | cd16bf6 | 2007-06-13 18:07:49 +0000 | [diff] [blame] | 150 | return self.VERSION, super().getstate(), self.gauss_next |
Tim Peters | cd80410 | 2001-01-25 20:25:57 +0000 | [diff] [blame] | 151 | |
| 152 | def setstate(self, state): |
| 153 | """Restore internal state from object returned by getstate().""" |
| 154 | version = state[0] |
Christian Heimes | cbf3b5c | 2007-12-03 21:02:03 +0000 | [diff] [blame] | 155 | if version == 3: |
Raymond Hettinger | 40f6217 | 2002-12-29 23:03:38 +0000 | [diff] [blame] | 156 | version, internalstate, self.gauss_next = state |
Guido van Rossum | cd16bf6 | 2007-06-13 18:07:49 +0000 | [diff] [blame] | 157 | super().setstate(internalstate) |
Christian Heimes | cbf3b5c | 2007-12-03 21:02:03 +0000 | [diff] [blame] | 158 | elif version == 2: |
| 159 | version, internalstate, self.gauss_next = state |
| 160 | # In version 2, the state was saved as signed ints, which causes |
| 161 | # inconsistencies between 32/64-bit systems. The state is |
| 162 | # really unsigned 32-bit ints, so we convert negative ints from |
| 163 | # version 2 to positive longs for version 3. |
| 164 | try: |
Raymond Hettinger | c585eec | 2010-09-07 15:00:15 +0000 | [diff] [blame] | 165 | internalstate = tuple(x % (2**32) for x in internalstate) |
Christian Heimes | cbf3b5c | 2007-12-03 21:02:03 +0000 | [diff] [blame] | 166 | except ValueError as e: |
| 167 | raise TypeError from e |
Raymond Hettinger | 183cd1f | 2010-09-08 18:48:21 +0000 | [diff] [blame] | 168 | super().setstate(internalstate) |
Tim Peters | cd80410 | 2001-01-25 20:25:57 +0000 | [diff] [blame] | 169 | else: |
| 170 | raise ValueError("state with version %s passed to " |
| 171 | "Random.setstate() of version %s" % |
| 172 | (version, self.VERSION)) |
| 173 | |
Tim Peters | cd80410 | 2001-01-25 20:25:57 +0000 | [diff] [blame] | 174 | ## ---- Methods below this point do not need to be overridden when |
| 175 | ## ---- subclassing for the purpose of using a different core generator. |
| 176 | |
| 177 | ## -------------------- pickle support ------------------- |
| 178 | |
R David Murray | d9ebf4d | 2013-04-02 13:10:52 -0400 | [diff] [blame] | 179 | # Issue 17489: Since __reduce__ was defined to fix #759889 this is no |
| 180 | # longer called; we leave it here because it has been here since random was |
| 181 | # rewritten back in 2001 and why risk breaking something. |
Tim Peters | cd80410 | 2001-01-25 20:25:57 +0000 | [diff] [blame] | 182 | def __getstate__(self): # for pickle |
| 183 | return self.getstate() |
| 184 | |
| 185 | def __setstate__(self, state): # for pickle |
| 186 | self.setstate(state) |
| 187 | |
Raymond Hettinger | 5f078ff | 2003-06-24 20:29:04 +0000 | [diff] [blame] | 188 | def __reduce__(self): |
| 189 | return self.__class__, (), self.getstate() |
| 190 | |
Tim Peters | cd80410 | 2001-01-25 20:25:57 +0000 | [diff] [blame] | 191 | ## -------------------- integer methods ------------------- |
| 192 | |
Raymond Hettinger | 8fe47c3 | 2013-10-05 21:48:21 -0700 | [diff] [blame] | 193 | def randrange(self, start, stop=None, step=1, _int=int): |
Tim Peters | d7b5e88 | 2001-01-25 03:36:26 +0000 | [diff] [blame] | 194 | """Choose a random item from range(start, stop[, step]). |
| 195 | |
| 196 | This fixes the problem with randint() which includes the |
| 197 | endpoint; in Python this is usually not what you want. |
Raymond Hettinger | 3051cc3 | 2010-09-07 00:48:40 +0000 | [diff] [blame] | 198 | |
Tim Peters | d7b5e88 | 2001-01-25 03:36:26 +0000 | [diff] [blame] | 199 | """ |
| 200 | |
| 201 | # This code is a bit messy to make it fast for the |
Tim Peters | 9146f27 | 2002-08-16 03:41:39 +0000 | [diff] [blame] | 202 | # common case while still doing adequate error checking. |
Raymond Hettinger | 8fe47c3 | 2013-10-05 21:48:21 -0700 | [diff] [blame] | 203 | istart = _int(start) |
Tim Peters | d7b5e88 | 2001-01-25 03:36:26 +0000 | [diff] [blame] | 204 | if istart != start: |
Collin Winter | ce36ad8 | 2007-08-30 01:19:48 +0000 | [diff] [blame] | 205 | raise ValueError("non-integer arg 1 for randrange()") |
Raymond Hettinger | 3051cc3 | 2010-09-07 00:48:40 +0000 | [diff] [blame] | 206 | if stop is None: |
Tim Peters | d7b5e88 | 2001-01-25 03:36:26 +0000 | [diff] [blame] | 207 | if istart > 0: |
Raymond Hettinger | 0515661 | 2010-09-07 04:44:52 +0000 | [diff] [blame] | 208 | return self._randbelow(istart) |
Collin Winter | ce36ad8 | 2007-08-30 01:19:48 +0000 | [diff] [blame] | 209 | raise ValueError("empty range for randrange()") |
Tim Peters | 9146f27 | 2002-08-16 03:41:39 +0000 | [diff] [blame] | 210 | |
| 211 | # stop argument supplied. |
Raymond Hettinger | 8fe47c3 | 2013-10-05 21:48:21 -0700 | [diff] [blame] | 212 | istop = _int(stop) |
Tim Peters | d7b5e88 | 2001-01-25 03:36:26 +0000 | [diff] [blame] | 213 | if istop != stop: |
Collin Winter | ce36ad8 | 2007-08-30 01:19:48 +0000 | [diff] [blame] | 214 | raise ValueError("non-integer stop for randrange()") |
Raymond Hettinger | 2f726e9 | 2003-10-05 09:09:15 +0000 | [diff] [blame] | 215 | width = istop - istart |
| 216 | if step == 1 and width > 0: |
Raymond Hettinger | c324697 | 2010-09-07 09:32:57 +0000 | [diff] [blame] | 217 | return istart + self._randbelow(width) |
Tim Peters | d7b5e88 | 2001-01-25 03:36:26 +0000 | [diff] [blame] | 218 | if step == 1: |
Collin Winter | ce36ad8 | 2007-08-30 01:19:48 +0000 | [diff] [blame] | 219 | raise ValueError("empty range for randrange() (%d,%d, %d)" % (istart, istop, width)) |
Tim Peters | 9146f27 | 2002-08-16 03:41:39 +0000 | [diff] [blame] | 220 | |
| 221 | # Non-unit step argument supplied. |
Raymond Hettinger | 8fe47c3 | 2013-10-05 21:48:21 -0700 | [diff] [blame] | 222 | istep = _int(step) |
Tim Peters | d7b5e88 | 2001-01-25 03:36:26 +0000 | [diff] [blame] | 223 | if istep != step: |
Collin Winter | ce36ad8 | 2007-08-30 01:19:48 +0000 | [diff] [blame] | 224 | raise ValueError("non-integer step for randrange()") |
Tim Peters | d7b5e88 | 2001-01-25 03:36:26 +0000 | [diff] [blame] | 225 | if istep > 0: |
Raymond Hettinger | ffdb8bb | 2004-09-27 15:29:05 +0000 | [diff] [blame] | 226 | n = (width + istep - 1) // istep |
Tim Peters | d7b5e88 | 2001-01-25 03:36:26 +0000 | [diff] [blame] | 227 | elif istep < 0: |
Raymond Hettinger | ffdb8bb | 2004-09-27 15:29:05 +0000 | [diff] [blame] | 228 | n = (width + istep + 1) // istep |
Tim Peters | d7b5e88 | 2001-01-25 03:36:26 +0000 | [diff] [blame] | 229 | else: |
Collin Winter | ce36ad8 | 2007-08-30 01:19:48 +0000 | [diff] [blame] | 230 | raise ValueError("zero step for randrange()") |
Tim Peters | d7b5e88 | 2001-01-25 03:36:26 +0000 | [diff] [blame] | 231 | |
| 232 | if n <= 0: |
Collin Winter | ce36ad8 | 2007-08-30 01:19:48 +0000 | [diff] [blame] | 233 | raise ValueError("empty range for randrange()") |
Raymond Hettinger | 2f726e9 | 2003-10-05 09:09:15 +0000 | [diff] [blame] | 234 | |
Raymond Hettinger | 0515661 | 2010-09-07 04:44:52 +0000 | [diff] [blame] | 235 | return istart + istep*self._randbelow(n) |
Tim Peters | d7b5e88 | 2001-01-25 03:36:26 +0000 | [diff] [blame] | 236 | |
| 237 | def randint(self, a, b): |
Tim Peters | cd80410 | 2001-01-25 20:25:57 +0000 | [diff] [blame] | 238 | """Return random integer in range [a, b], including both end points. |
Tim Peters | d7b5e88 | 2001-01-25 03:36:26 +0000 | [diff] [blame] | 239 | """ |
| 240 | |
| 241 | return self.randrange(a, b+1) |
| 242 | |
Wolfgang Maier | ba3a87a | 2018-04-17 17:16:17 +0200 | [diff] [blame] | 243 | def _randbelow_with_getrandbits(self, n): |
Raymond Hettinger | e4a3e99 | 2010-09-08 00:30:28 +0000 | [diff] [blame] | 244 | "Return a random int in the range [0,n). Raises ValueError if n==0." |
Raymond Hettinger | 2f726e9 | 2003-10-05 09:09:15 +0000 | [diff] [blame] | 245 | |
Raymond Hettinger | c324697 | 2010-09-07 09:32:57 +0000 | [diff] [blame] | 246 | getrandbits = self.getrandbits |
Wolfgang Maier | ba3a87a | 2018-04-17 17:16:17 +0200 | [diff] [blame] | 247 | k = n.bit_length() # don't use (n-1) here because n can be 1 |
| 248 | r = getrandbits(k) # 0 <= r < 2**k |
| 249 | while r >= n: |
| 250 | r = getrandbits(k) |
| 251 | return r |
| 252 | |
| 253 | def _randbelow_without_getrandbits(self, n, int=int, maxsize=1<<BPF): |
| 254 | """Return a random int in the range [0,n). Raises ValueError if n==0. |
| 255 | |
| 256 | The implementation does not use getrandbits, but only random. |
| 257 | """ |
| 258 | |
| 259 | random = self.random |
Raymond Hettinger | e4a3e99 | 2010-09-08 00:30:28 +0000 | [diff] [blame] | 260 | if n >= maxsize: |
Raymond Hettinger | 2f726e9 | 2003-10-05 09:09:15 +0000 | [diff] [blame] | 261 | _warn("Underlying random() generator does not supply \n" |
Raymond Hettinger | f015b3f | 2010-09-07 20:04:42 +0000 | [diff] [blame] | 262 | "enough bits to choose from a population range this large.\n" |
| 263 | "To remove the range limitation, add a getrandbits() method.") |
Raymond Hettinger | e4a3e99 | 2010-09-08 00:30:28 +0000 | [diff] [blame] | 264 | return int(random() * n) |
Wolfgang Maier | 091e95e | 2018-04-05 17:19:44 +0200 | [diff] [blame] | 265 | if n == 0: |
| 266 | raise ValueError("Boundary cannot be zero") |
Raymond Hettinger | e4a3e99 | 2010-09-08 00:30:28 +0000 | [diff] [blame] | 267 | rem = maxsize % n |
| 268 | limit = (maxsize - rem) / maxsize # int(limit * maxsize) % n == 0 |
| 269 | r = random() |
| 270 | while r >= limit: |
| 271 | r = random() |
| 272 | return int(r*maxsize) % n |
Raymond Hettinger | 2f726e9 | 2003-10-05 09:09:15 +0000 | [diff] [blame] | 273 | |
Wolfgang Maier | ba3a87a | 2018-04-17 17:16:17 +0200 | [diff] [blame] | 274 | _randbelow = _randbelow_with_getrandbits |
| 275 | |
Tim Peters | cd80410 | 2001-01-25 20:25:57 +0000 | [diff] [blame] | 276 | ## -------------------- sequence methods ------------------- |
| 277 | |
Tim Peters | d7b5e88 | 2001-01-25 03:36:26 +0000 | [diff] [blame] | 278 | def choice(self, seq): |
| 279 | """Choose a random element from a non-empty sequence.""" |
Raymond Hettinger | dc4872e | 2010-09-07 10:06:56 +0000 | [diff] [blame] | 280 | try: |
| 281 | i = self._randbelow(len(seq)) |
| 282 | except ValueError: |
Raymond Hettinger | bb2839b | 2016-12-27 01:06:52 -0800 | [diff] [blame] | 283 | raise IndexError('Cannot choose from an empty sequence') from None |
Raymond Hettinger | dc4872e | 2010-09-07 10:06:56 +0000 | [diff] [blame] | 284 | return seq[i] |
Tim Peters | d7b5e88 | 2001-01-25 03:36:26 +0000 | [diff] [blame] | 285 | |
Raymond Hettinger | 8fe47c3 | 2013-10-05 21:48:21 -0700 | [diff] [blame] | 286 | def shuffle(self, x, random=None): |
Antoine Pitrou | 5e39433 | 2012-11-04 02:10:33 +0100 | [diff] [blame] | 287 | """Shuffle list x in place, and return None. |
Tim Peters | d7b5e88 | 2001-01-25 03:36:26 +0000 | [diff] [blame] | 288 | |
Antoine Pitrou | 5e39433 | 2012-11-04 02:10:33 +0100 | [diff] [blame] | 289 | Optional argument random is a 0-argument function returning a |
| 290 | random float in [0.0, 1.0); if it is the default None, the |
| 291 | standard random.random will be used. |
Senthil Kumaran | f8ce51a | 2013-09-11 22:54:31 -0700 | [diff] [blame] | 292 | |
Tim Peters | d7b5e88 | 2001-01-25 03:36:26 +0000 | [diff] [blame] | 293 | """ |
| 294 | |
Raymond Hettinger | 8fe47c3 | 2013-10-05 21:48:21 -0700 | [diff] [blame] | 295 | if random is None: |
| 296 | randbelow = self._randbelow |
| 297 | for i in reversed(range(1, len(x))): |
| 298 | # pick an element in x[:i+1] with which to exchange x[i] |
| 299 | j = randbelow(i+1) |
| 300 | x[i], x[j] = x[j], x[i] |
| 301 | else: |
| 302 | _int = int |
| 303 | for i in reversed(range(1, len(x))): |
| 304 | # pick an element in x[:i+1] with which to exchange x[i] |
| 305 | j = _int(random() * (i+1)) |
| 306 | x[i], x[j] = x[j], x[i] |
Tim Peters | d7b5e88 | 2001-01-25 03:36:26 +0000 | [diff] [blame] | 307 | |
Raymond Hettinger | fdbe522 | 2003-06-13 07:01:51 +0000 | [diff] [blame] | 308 | def sample(self, population, k): |
Raymond Hettinger | 1acde19 | 2008-01-14 01:00:53 +0000 | [diff] [blame] | 309 | """Chooses k unique random elements from a population sequence or set. |
Raymond Hettinger | f24eb35 | 2002-11-12 17:41:57 +0000 | [diff] [blame] | 310 | |
Raymond Hettinger | c0b4034 | 2002-11-13 15:26:37 +0000 | [diff] [blame] | 311 | Returns a new list containing elements from the population while |
| 312 | leaving the original population unchanged. The resulting list is |
| 313 | in selection order so that all sub-slices will also be valid random |
| 314 | samples. This allows raffle winners (the sample) to be partitioned |
| 315 | into grand prize and second place winners (the subslices). |
Raymond Hettinger | f24eb35 | 2002-11-12 17:41:57 +0000 | [diff] [blame] | 316 | |
Raymond Hettinger | c0b4034 | 2002-11-13 15:26:37 +0000 | [diff] [blame] | 317 | Members of the population need not be hashable or unique. If the |
| 318 | population contains repeats, then each occurrence is a possible |
| 319 | selection in the sample. |
Raymond Hettinger | f24eb35 | 2002-11-12 17:41:57 +0000 | [diff] [blame] | 320 | |
Guido van Rossum | 805365e | 2007-05-07 22:24:25 +0000 | [diff] [blame] | 321 | To choose a sample in a range of integers, use range as an argument. |
Raymond Hettinger | c0b4034 | 2002-11-13 15:26:37 +0000 | [diff] [blame] | 322 | This is especially fast and space efficient for sampling from a |
Guido van Rossum | 805365e | 2007-05-07 22:24:25 +0000 | [diff] [blame] | 323 | large population: sample(range(10000000), 60) |
Raymond Hettinger | f24eb35 | 2002-11-12 17:41:57 +0000 | [diff] [blame] | 324 | """ |
| 325 | |
Raymond Hettinger | c0b4034 | 2002-11-13 15:26:37 +0000 | [diff] [blame] | 326 | # Sampling without replacement entails tracking either potential |
Raymond Hettinger | 91e27c2 | 2005-08-19 01:36:35 +0000 | [diff] [blame] | 327 | # selections (the pool) in a list or previous selections in a set. |
Raymond Hettinger | c0b4034 | 2002-11-13 15:26:37 +0000 | [diff] [blame] | 328 | |
Jeremy Hylton | 2b55d35 | 2004-02-23 17:27:57 +0000 | [diff] [blame] | 329 | # When the number of selections is small compared to the |
| 330 | # population, then tracking selections is efficient, requiring |
Raymond Hettinger | 91e27c2 | 2005-08-19 01:36:35 +0000 | [diff] [blame] | 331 | # only a small set and an occasional reselection. For |
Jeremy Hylton | 2b55d35 | 2004-02-23 17:27:57 +0000 | [diff] [blame] | 332 | # a larger number of selections, the pool tracking method is |
| 333 | # preferred since the list takes less space than the |
Raymond Hettinger | 91e27c2 | 2005-08-19 01:36:35 +0000 | [diff] [blame] | 334 | # set and it doesn't suffer from frequent reselections. |
Raymond Hettinger | c0b4034 | 2002-11-13 15:26:37 +0000 | [diff] [blame] | 335 | |
Raymond Hettinger | 57d1a88 | 2011-02-23 00:46:28 +0000 | [diff] [blame] | 336 | if isinstance(population, _Set): |
Raymond Hettinger | 1acde19 | 2008-01-14 01:00:53 +0000 | [diff] [blame] | 337 | population = tuple(population) |
Raymond Hettinger | 57d1a88 | 2011-02-23 00:46:28 +0000 | [diff] [blame] | 338 | if not isinstance(population, _Sequence): |
| 339 | raise TypeError("Population must be a sequence or set. For dicts, use list(d).") |
Raymond Hettinger | 05a505f | 2010-09-07 19:19:33 +0000 | [diff] [blame] | 340 | randbelow = self._randbelow |
Raymond Hettinger | f24eb35 | 2002-11-12 17:41:57 +0000 | [diff] [blame] | 341 | n = len(population) |
| 342 | if not 0 <= k <= n: |
Raymond Hettinger | bf87126 | 2016-11-21 14:34:33 -0800 | [diff] [blame] | 343 | raise ValueError("Sample larger than population or is negative") |
Raymond Hettinger | c0b4034 | 2002-11-13 15:26:37 +0000 | [diff] [blame] | 344 | result = [None] * k |
Raymond Hettinger | 91e27c2 | 2005-08-19 01:36:35 +0000 | [diff] [blame] | 345 | setsize = 21 # size of a small set minus size of an empty list |
| 346 | if k > 5: |
Tim Peters | 9e34c04 | 2005-08-26 15:20:46 +0000 | [diff] [blame] | 347 | setsize += 4 ** _ceil(_log(k * 3, 4)) # table size for big sets |
Raymond Hettinger | 1acde19 | 2008-01-14 01:00:53 +0000 | [diff] [blame] | 348 | if n <= setsize: |
| 349 | # An n-length list is smaller than a k-length set |
Raymond Hettinger | 311f419 | 2002-11-18 09:01:24 +0000 | [diff] [blame] | 350 | pool = list(population) |
Guido van Rossum | 805365e | 2007-05-07 22:24:25 +0000 | [diff] [blame] | 351 | for i in range(k): # invariant: non-selected at [0,n-i) |
Raymond Hettinger | 05a505f | 2010-09-07 19:19:33 +0000 | [diff] [blame] | 352 | j = randbelow(n-i) |
Raymond Hettinger | 311f419 | 2002-11-18 09:01:24 +0000 | [diff] [blame] | 353 | result[i] = pool[j] |
Raymond Hettinger | 8b9aa8d | 2003-01-04 05:20:33 +0000 | [diff] [blame] | 354 | pool[j] = pool[n-i-1] # move non-selected item into vacancy |
Raymond Hettinger | c0b4034 | 2002-11-13 15:26:37 +0000 | [diff] [blame] | 355 | else: |
Raymond Hettinger | 1acde19 | 2008-01-14 01:00:53 +0000 | [diff] [blame] | 356 | selected = set() |
| 357 | selected_add = selected.add |
| 358 | for i in range(k): |
Raymond Hettinger | 05a505f | 2010-09-07 19:19:33 +0000 | [diff] [blame] | 359 | j = randbelow(n) |
Raymond Hettinger | 1acde19 | 2008-01-14 01:00:53 +0000 | [diff] [blame] | 360 | while j in selected: |
Raymond Hettinger | 05a505f | 2010-09-07 19:19:33 +0000 | [diff] [blame] | 361 | j = randbelow(n) |
Raymond Hettinger | 1acde19 | 2008-01-14 01:00:53 +0000 | [diff] [blame] | 362 | selected_add(j) |
| 363 | result[i] = population[j] |
Raymond Hettinger | 311f419 | 2002-11-18 09:01:24 +0000 | [diff] [blame] | 364 | return result |
Raymond Hettinger | f24eb35 | 2002-11-12 17:41:57 +0000 | [diff] [blame] | 365 | |
Raymond Hettinger | 9016f28 | 2016-09-26 21:45:57 -0700 | [diff] [blame] | 366 | def choices(self, population, weights=None, *, cum_weights=None, k=1): |
Raymond Hettinger | e8f1e00 | 2016-09-06 17:15:29 -0700 | [diff] [blame] | 367 | """Return a k sized list of population elements chosen with replacement. |
| 368 | |
| 369 | If the relative weights or cumulative weights are not specified, |
| 370 | the selections are made with equal probability. |
| 371 | |
| 372 | """ |
Raymond Hettinger | 30d00e5 | 2016-10-29 16:55:36 -0700 | [diff] [blame] | 373 | random = self.random |
Raymond Hettinger | e69cd16 | 2018-07-04 15:28:20 -0700 | [diff] [blame] | 374 | n = len(population) |
Raymond Hettinger | e8f1e00 | 2016-09-06 17:15:29 -0700 | [diff] [blame] | 375 | if cum_weights is None: |
| 376 | if weights is None: |
Raymond Hettinger | 30d00e5 | 2016-10-29 16:55:36 -0700 | [diff] [blame] | 377 | _int = int |
Raymond Hettinger | e69cd16 | 2018-07-04 15:28:20 -0700 | [diff] [blame] | 378 | return [population[_int(random() * n)] for i in range(k)] |
Raymond Hettinger | 8567e58 | 2016-11-01 22:23:11 -0700 | [diff] [blame] | 379 | cum_weights = list(_itertools.accumulate(weights)) |
Raymond Hettinger | e8f1e00 | 2016-09-06 17:15:29 -0700 | [diff] [blame] | 380 | elif weights is not None: |
Raymond Hettinger | 24e4239 | 2016-11-13 00:42:56 -0500 | [diff] [blame] | 381 | raise TypeError('Cannot specify both weights and cumulative weights') |
Raymond Hettinger | e69cd16 | 2018-07-04 15:28:20 -0700 | [diff] [blame] | 382 | if len(cum_weights) != n: |
Raymond Hettinger | e8f1e00 | 2016-09-06 17:15:29 -0700 | [diff] [blame] | 383 | raise ValueError('The number of weights does not match the population') |
| 384 | bisect = _bisect.bisect |
Raymond Hettinger | e8f1e00 | 2016-09-06 17:15:29 -0700 | [diff] [blame] | 385 | total = cum_weights[-1] |
Raymond Hettinger | e69cd16 | 2018-07-04 15:28:20 -0700 | [diff] [blame] | 386 | hi = n - 1 |
Raymond Hettinger | ddf7171 | 2018-06-27 01:08:31 -0700 | [diff] [blame] | 387 | return [population[bisect(cum_weights, random() * total, 0, hi)] |
| 388 | for i in range(k)] |
Raymond Hettinger | e8f1e00 | 2016-09-06 17:15:29 -0700 | [diff] [blame] | 389 | |
Tim Peters | cd80410 | 2001-01-25 20:25:57 +0000 | [diff] [blame] | 390 | ## -------------------- real-valued distributions ------------------- |
| 391 | |
| 392 | ## -------------------- uniform distribution ------------------- |
Tim Peters | d7b5e88 | 2001-01-25 03:36:26 +0000 | [diff] [blame] | 393 | |
| 394 | def uniform(self, a, b): |
Raymond Hettinger | be40db0 | 2009-06-11 23:12:14 +0000 | [diff] [blame] | 395 | "Get a random number in the range [a, b) or [a, b] depending on rounding." |
Tim Peters | d7b5e88 | 2001-01-25 03:36:26 +0000 | [diff] [blame] | 396 | return a + (b-a) * self.random() |
Guido van Rossum | ff03b1a | 1994-03-09 12:55:02 +0000 | [diff] [blame] | 397 | |
Christian Heimes | fe337bf | 2008-03-23 21:54:12 +0000 | [diff] [blame] | 398 | ## -------------------- triangular -------------------- |
| 399 | |
| 400 | def triangular(self, low=0.0, high=1.0, mode=None): |
| 401 | """Triangular distribution. |
| 402 | |
| 403 | Continuous distribution bounded by given lower and upper limits, |
| 404 | and having a given mode value in-between. |
| 405 | |
| 406 | http://en.wikipedia.org/wiki/Triangular_distribution |
| 407 | |
| 408 | """ |
| 409 | u = self.random() |
Raymond Hettinger | 978c6ab | 2014-05-25 17:25:27 -0700 | [diff] [blame] | 410 | try: |
| 411 | c = 0.5 if mode is None else (mode - low) / (high - low) |
| 412 | except ZeroDivisionError: |
| 413 | return low |
Christian Heimes | fe337bf | 2008-03-23 21:54:12 +0000 | [diff] [blame] | 414 | if u > c: |
| 415 | u = 1.0 - u |
| 416 | c = 1.0 - c |
| 417 | low, high = high, low |
Raymond Hettinger | f5ea83f | 2017-09-04 16:51:06 -0700 | [diff] [blame] | 418 | return low + (high - low) * _sqrt(u * c) |
Christian Heimes | fe337bf | 2008-03-23 21:54:12 +0000 | [diff] [blame] | 419 | |
Tim Peters | cd80410 | 2001-01-25 20:25:57 +0000 | [diff] [blame] | 420 | ## -------------------- normal distribution -------------------- |
Guido van Rossum | ff03b1a | 1994-03-09 12:55:02 +0000 | [diff] [blame] | 421 | |
Tim Peters | d7b5e88 | 2001-01-25 03:36:26 +0000 | [diff] [blame] | 422 | def normalvariate(self, mu, sigma): |
Raymond Hettinger | c32f033 | 2002-05-23 19:44:49 +0000 | [diff] [blame] | 423 | """Normal distribution. |
| 424 | |
| 425 | mu is the mean, and sigma is the standard deviation. |
Raymond Hettinger | ef4d4bd | 2002-05-23 23:58:17 +0000 | [diff] [blame] | 426 | |
Raymond Hettinger | c32f033 | 2002-05-23 19:44:49 +0000 | [diff] [blame] | 427 | """ |
Tim Peters | d7b5e88 | 2001-01-25 03:36:26 +0000 | [diff] [blame] | 428 | # mu = mean, sigma = standard deviation |
Guido van Rossum | ff03b1a | 1994-03-09 12:55:02 +0000 | [diff] [blame] | 429 | |
Tim Peters | d7b5e88 | 2001-01-25 03:36:26 +0000 | [diff] [blame] | 430 | # Uses Kinderman and Monahan method. Reference: Kinderman, |
| 431 | # A.J. and Monahan, J.F., "Computer generation of random |
| 432 | # variables using the ratio of uniform deviates", ACM Trans |
| 433 | # Math Software, 3, (1977), pp257-260. |
Guido van Rossum | ff03b1a | 1994-03-09 12:55:02 +0000 | [diff] [blame] | 434 | |
Tim Peters | d7b5e88 | 2001-01-25 03:36:26 +0000 | [diff] [blame] | 435 | random = self.random |
Raymond Hettinger | 42406e6 | 2005-04-30 09:02:51 +0000 | [diff] [blame] | 436 | while 1: |
Tim Peters | 0c9886d | 2001-01-15 01:18:21 +0000 | [diff] [blame] | 437 | u1 = random() |
Raymond Hettinger | 73ced7e | 2003-01-04 09:26:32 +0000 | [diff] [blame] | 438 | u2 = 1.0 - random() |
Tim Peters | d7b5e88 | 2001-01-25 03:36:26 +0000 | [diff] [blame] | 439 | z = NV_MAGICCONST*(u1-0.5)/u2 |
| 440 | zz = z*z/4.0 |
| 441 | if zz <= -_log(u2): |
| 442 | break |
| 443 | return mu + z*sigma |
Guido van Rossum | ff03b1a | 1994-03-09 12:55:02 +0000 | [diff] [blame] | 444 | |
Tim Peters | cd80410 | 2001-01-25 20:25:57 +0000 | [diff] [blame] | 445 | ## -------------------- lognormal distribution -------------------- |
Tim Peters | d7b5e88 | 2001-01-25 03:36:26 +0000 | [diff] [blame] | 446 | |
| 447 | def lognormvariate(self, mu, sigma): |
Raymond Hettinger | c32f033 | 2002-05-23 19:44:49 +0000 | [diff] [blame] | 448 | """Log normal distribution. |
| 449 | |
| 450 | If you take the natural logarithm of this distribution, you'll get a |
| 451 | normal distribution with mean mu and standard deviation sigma. |
| 452 | mu can have any value, and sigma must be greater than zero. |
Raymond Hettinger | ef4d4bd | 2002-05-23 23:58:17 +0000 | [diff] [blame] | 453 | |
Raymond Hettinger | c32f033 | 2002-05-23 19:44:49 +0000 | [diff] [blame] | 454 | """ |
Tim Peters | d7b5e88 | 2001-01-25 03:36:26 +0000 | [diff] [blame] | 455 | return _exp(self.normalvariate(mu, sigma)) |
| 456 | |
Tim Peters | cd80410 | 2001-01-25 20:25:57 +0000 | [diff] [blame] | 457 | ## -------------------- exponential distribution -------------------- |
Tim Peters | d7b5e88 | 2001-01-25 03:36:26 +0000 | [diff] [blame] | 458 | |
| 459 | def expovariate(self, lambd): |
Raymond Hettinger | c32f033 | 2002-05-23 19:44:49 +0000 | [diff] [blame] | 460 | """Exponential distribution. |
| 461 | |
Mark Dickinson | 2f94736 | 2009-01-07 17:54:07 +0000 | [diff] [blame] | 462 | lambd is 1.0 divided by the desired mean. It should be |
| 463 | nonzero. (The parameter would be called "lambda", but that is |
| 464 | a reserved word in Python.) Returned values range from 0 to |
| 465 | positive infinity if lambd is positive, and from negative |
| 466 | infinity to 0 if lambd is negative. |
Raymond Hettinger | ef4d4bd | 2002-05-23 23:58:17 +0000 | [diff] [blame] | 467 | |
Raymond Hettinger | c32f033 | 2002-05-23 19:44:49 +0000 | [diff] [blame] | 468 | """ |
Tim Peters | d7b5e88 | 2001-01-25 03:36:26 +0000 | [diff] [blame] | 469 | # lambd: rate lambd = 1/mean |
| 470 | # ('lambda' is a Python reserved word) |
| 471 | |
Raymond Hettinger | 5279fb9 | 2011-06-25 11:30:53 +0200 | [diff] [blame] | 472 | # we use 1-random() instead of random() to preclude the |
| 473 | # possibility of taking the log of zero. |
| 474 | return -_log(1.0 - self.random())/lambd |
Guido van Rossum | ff03b1a | 1994-03-09 12:55:02 +0000 | [diff] [blame] | 475 | |
Tim Peters | cd80410 | 2001-01-25 20:25:57 +0000 | [diff] [blame] | 476 | ## -------------------- von Mises distribution -------------------- |
Guido van Rossum | ff03b1a | 1994-03-09 12:55:02 +0000 | [diff] [blame] | 477 | |
Tim Peters | d7b5e88 | 2001-01-25 03:36:26 +0000 | [diff] [blame] | 478 | def vonmisesvariate(self, mu, kappa): |
Raymond Hettinger | c32f033 | 2002-05-23 19:44:49 +0000 | [diff] [blame] | 479 | """Circular data distribution. |
Raymond Hettinger | ef4d4bd | 2002-05-23 23:58:17 +0000 | [diff] [blame] | 480 | |
Raymond Hettinger | c32f033 | 2002-05-23 19:44:49 +0000 | [diff] [blame] | 481 | mu is the mean angle, expressed in radians between 0 and 2*pi, and |
| 482 | kappa is the concentration parameter, which must be greater than or |
| 483 | equal to zero. If kappa is equal to zero, this distribution reduces |
| 484 | to a uniform random angle over the range 0 to 2*pi. |
Raymond Hettinger | ef4d4bd | 2002-05-23 23:58:17 +0000 | [diff] [blame] | 485 | |
Raymond Hettinger | c32f033 | 2002-05-23 19:44:49 +0000 | [diff] [blame] | 486 | """ |
Tim Peters | d7b5e88 | 2001-01-25 03:36:26 +0000 | [diff] [blame] | 487 | # mu: mean angle (in radians between 0 and 2*pi) |
| 488 | # kappa: concentration parameter kappa (>= 0) |
| 489 | # if kappa = 0 generate uniform random angle |
| 490 | |
| 491 | # Based upon an algorithm published in: Fisher, N.I., |
| 492 | # "Statistical Analysis of Circular Data", Cambridge |
| 493 | # University Press, 1993. |
| 494 | |
| 495 | # Thanks to Magnus Kessler for a correction to the |
| 496 | # implementation of step 4. |
| 497 | |
| 498 | random = self.random |
| 499 | if kappa <= 1e-6: |
| 500 | return TWOPI * random() |
| 501 | |
Serhiy Storchaka | 6c22b1d | 2013-02-10 19:28:56 +0200 | [diff] [blame] | 502 | s = 0.5 / kappa |
| 503 | r = s + _sqrt(1.0 + s * s) |
Guido van Rossum | ff03b1a | 1994-03-09 12:55:02 +0000 | [diff] [blame] | 504 | |
Raymond Hettinger | 42406e6 | 2005-04-30 09:02:51 +0000 | [diff] [blame] | 505 | while 1: |
Tim Peters | 0c9886d | 2001-01-15 01:18:21 +0000 | [diff] [blame] | 506 | u1 = random() |
Tim Peters | d7b5e88 | 2001-01-25 03:36:26 +0000 | [diff] [blame] | 507 | z = _cos(_pi * u1) |
Tim Peters | d7b5e88 | 2001-01-25 03:36:26 +0000 | [diff] [blame] | 508 | |
Serhiy Storchaka | 6c22b1d | 2013-02-10 19:28:56 +0200 | [diff] [blame] | 509 | d = z / (r + z) |
Tim Peters | d7b5e88 | 2001-01-25 03:36:26 +0000 | [diff] [blame] | 510 | u2 = random() |
Serhiy Storchaka | 6c22b1d | 2013-02-10 19:28:56 +0200 | [diff] [blame] | 511 | if u2 < 1.0 - d * d or u2 <= (1.0 - d) * _exp(d): |
Tim Peters | 0c9886d | 2001-01-15 01:18:21 +0000 | [diff] [blame] | 512 | break |
Tim Peters | d7b5e88 | 2001-01-25 03:36:26 +0000 | [diff] [blame] | 513 | |
Serhiy Storchaka | 6c22b1d | 2013-02-10 19:28:56 +0200 | [diff] [blame] | 514 | q = 1.0 / r |
| 515 | f = (q + z) / (1.0 + q * z) |
Tim Peters | d7b5e88 | 2001-01-25 03:36:26 +0000 | [diff] [blame] | 516 | u3 = random() |
| 517 | if u3 > 0.5: |
Mark Dickinson | be5f919 | 2013-02-10 14:16:10 +0000 | [diff] [blame] | 518 | theta = (mu + _acos(f)) % TWOPI |
Tim Peters | d7b5e88 | 2001-01-25 03:36:26 +0000 | [diff] [blame] | 519 | else: |
Mark Dickinson | be5f919 | 2013-02-10 14:16:10 +0000 | [diff] [blame] | 520 | theta = (mu - _acos(f)) % TWOPI |
Tim Peters | d7b5e88 | 2001-01-25 03:36:26 +0000 | [diff] [blame] | 521 | |
| 522 | return theta |
| 523 | |
Tim Peters | cd80410 | 2001-01-25 20:25:57 +0000 | [diff] [blame] | 524 | ## -------------------- gamma distribution -------------------- |
Tim Peters | d7b5e88 | 2001-01-25 03:36:26 +0000 | [diff] [blame] | 525 | |
| 526 | def gammavariate(self, alpha, beta): |
Raymond Hettinger | c32f033 | 2002-05-23 19:44:49 +0000 | [diff] [blame] | 527 | """Gamma distribution. Not the gamma function! |
| 528 | |
| 529 | Conditions on the parameters are alpha > 0 and beta > 0. |
| 530 | |
Raymond Hettinger | a8e4d6e | 2011-03-22 15:55:51 -0700 | [diff] [blame] | 531 | The probability distribution function is: |
| 532 | |
| 533 | x ** (alpha - 1) * math.exp(-x / beta) |
| 534 | pdf(x) = -------------------------------------- |
| 535 | math.gamma(alpha) * beta ** alpha |
| 536 | |
Raymond Hettinger | c32f033 | 2002-05-23 19:44:49 +0000 | [diff] [blame] | 537 | """ |
Tim Peters | 8ac1495 | 2002-05-23 15:15:30 +0000 | [diff] [blame] | 538 | |
Raymond Hettinger | b760efb | 2002-05-14 06:40:34 +0000 | [diff] [blame] | 539 | # alpha > 0, beta > 0, mean is alpha*beta, variance is alpha*beta**2 |
Tim Peters | 8ac1495 | 2002-05-23 15:15:30 +0000 | [diff] [blame] | 540 | |
Guido van Rossum | 570764d | 2002-05-14 14:08:12 +0000 | [diff] [blame] | 541 | # Warning: a few older sources define the gamma distribution in terms |
| 542 | # of alpha > -1.0 |
| 543 | if alpha <= 0.0 or beta <= 0.0: |
Collin Winter | ce36ad8 | 2007-08-30 01:19:48 +0000 | [diff] [blame] | 544 | raise ValueError('gammavariate: alpha and beta must be > 0.0') |
Tim Peters | 8ac1495 | 2002-05-23 15:15:30 +0000 | [diff] [blame] | 545 | |
Tim Peters | d7b5e88 | 2001-01-25 03:36:26 +0000 | [diff] [blame] | 546 | random = self.random |
Tim Peters | d7b5e88 | 2001-01-25 03:36:26 +0000 | [diff] [blame] | 547 | if alpha > 1.0: |
| 548 | |
| 549 | # Uses R.C.H. Cheng, "The generation of Gamma |
| 550 | # variables with non-integral shape parameters", |
| 551 | # Applied Statistics, (1977), 26, No. 1, p71-74 |
| 552 | |
Raymond Hettinger | ca6cdc2 | 2002-05-13 23:40:14 +0000 | [diff] [blame] | 553 | ainv = _sqrt(2.0 * alpha - 1.0) |
| 554 | bbb = alpha - LOG4 |
| 555 | ccc = alpha + ainv |
Tim Peters | 8ac1495 | 2002-05-23 15:15:30 +0000 | [diff] [blame] | 556 | |
Raymond Hettinger | 42406e6 | 2005-04-30 09:02:51 +0000 | [diff] [blame] | 557 | while 1: |
Tim Peters | d7b5e88 | 2001-01-25 03:36:26 +0000 | [diff] [blame] | 558 | u1 = random() |
Raymond Hettinger | 73ced7e | 2003-01-04 09:26:32 +0000 | [diff] [blame] | 559 | if not 1e-7 < u1 < .9999999: |
| 560 | continue |
| 561 | u2 = 1.0 - random() |
Tim Peters | d7b5e88 | 2001-01-25 03:36:26 +0000 | [diff] [blame] | 562 | v = _log(u1/(1.0-u1))/ainv |
| 563 | x = alpha*_exp(v) |
| 564 | z = u1*u1*u2 |
| 565 | r = bbb+ccc*v-x |
| 566 | if r + SG_MAGICCONST - 4.5*z >= 0.0 or r >= _log(z): |
Raymond Hettinger | b760efb | 2002-05-14 06:40:34 +0000 | [diff] [blame] | 567 | return x * beta |
Tim Peters | d7b5e88 | 2001-01-25 03:36:26 +0000 | [diff] [blame] | 568 | |
| 569 | elif alpha == 1.0: |
leodema | 9f396b6 | 2017-06-04 07:41:41 +0100 | [diff] [blame] | 570 | # expovariate(1/beta) |
Tim Peters | d7b5e88 | 2001-01-25 03:36:26 +0000 | [diff] [blame] | 571 | u = random() |
| 572 | while u <= 1e-7: |
| 573 | u = random() |
Raymond Hettinger | b760efb | 2002-05-14 06:40:34 +0000 | [diff] [blame] | 574 | return -_log(u) * beta |
Tim Peters | d7b5e88 | 2001-01-25 03:36:26 +0000 | [diff] [blame] | 575 | |
| 576 | else: # alpha is between 0 and 1 (exclusive) |
| 577 | |
| 578 | # Uses ALGORITHM GS of Statistical Computing - Kennedy & Gentle |
| 579 | |
Raymond Hettinger | 42406e6 | 2005-04-30 09:02:51 +0000 | [diff] [blame] | 580 | while 1: |
Tim Peters | d7b5e88 | 2001-01-25 03:36:26 +0000 | [diff] [blame] | 581 | u = random() |
| 582 | b = (_e + alpha)/_e |
| 583 | p = b*u |
| 584 | if p <= 1.0: |
Raymond Hettinger | 42406e6 | 2005-04-30 09:02:51 +0000 | [diff] [blame] | 585 | x = p ** (1.0/alpha) |
Tim Peters | d7b5e88 | 2001-01-25 03:36:26 +0000 | [diff] [blame] | 586 | else: |
Tim Peters | d7b5e88 | 2001-01-25 03:36:26 +0000 | [diff] [blame] | 587 | x = -_log((b-p)/alpha) |
| 588 | u1 = random() |
Raymond Hettinger | 42406e6 | 2005-04-30 09:02:51 +0000 | [diff] [blame] | 589 | if p > 1.0: |
| 590 | if u1 <= x ** (alpha - 1.0): |
| 591 | break |
| 592 | elif u1 <= _exp(-x): |
Tim Peters | d7b5e88 | 2001-01-25 03:36:26 +0000 | [diff] [blame] | 593 | break |
Raymond Hettinger | b760efb | 2002-05-14 06:40:34 +0000 | [diff] [blame] | 594 | return x * beta |
| 595 | |
Tim Peters | cd80410 | 2001-01-25 20:25:57 +0000 | [diff] [blame] | 596 | ## -------------------- Gauss (faster alternative) -------------------- |
Guido van Rossum | 95bfcda | 1994-03-09 14:21:05 +0000 | [diff] [blame] | 597 | |
Tim Peters | d7b5e88 | 2001-01-25 03:36:26 +0000 | [diff] [blame] | 598 | def gauss(self, mu, sigma): |
Raymond Hettinger | c32f033 | 2002-05-23 19:44:49 +0000 | [diff] [blame] | 599 | """Gaussian distribution. |
| 600 | |
| 601 | mu is the mean, and sigma is the standard deviation. This is |
| 602 | slightly faster than the normalvariate() function. |
| 603 | |
| 604 | Not thread-safe without a lock around calls. |
Raymond Hettinger | ef4d4bd | 2002-05-23 23:58:17 +0000 | [diff] [blame] | 605 | |
Raymond Hettinger | c32f033 | 2002-05-23 19:44:49 +0000 | [diff] [blame] | 606 | """ |
Guido van Rossum | cc32ac9 | 1994-03-15 16:10:24 +0000 | [diff] [blame] | 607 | |
Tim Peters | d7b5e88 | 2001-01-25 03:36:26 +0000 | [diff] [blame] | 608 | # When x and y are two variables from [0, 1), uniformly |
| 609 | # distributed, then |
| 610 | # |
| 611 | # cos(2*pi*x)*sqrt(-2*log(1-y)) |
| 612 | # sin(2*pi*x)*sqrt(-2*log(1-y)) |
| 613 | # |
| 614 | # are two *independent* variables with normal distribution |
| 615 | # (mu = 0, sigma = 1). |
| 616 | # (Lambert Meertens) |
| 617 | # (corrected version; bug discovered by Mike Miller, fixed by LM) |
Guido van Rossum | cc32ac9 | 1994-03-15 16:10:24 +0000 | [diff] [blame] | 618 | |
Tim Peters | d7b5e88 | 2001-01-25 03:36:26 +0000 | [diff] [blame] | 619 | # Multithreading note: When two threads call this function |
| 620 | # simultaneously, it is possible that they will receive the |
| 621 | # same return value. The window is very small though. To |
| 622 | # avoid this, you have to use a lock around all calls. (I |
| 623 | # didn't want to slow this down in the serial case by using a |
| 624 | # lock here.) |
Guido van Rossum | d03e119 | 1998-05-29 17:51:31 +0000 | [diff] [blame] | 625 | |
Tim Peters | d7b5e88 | 2001-01-25 03:36:26 +0000 | [diff] [blame] | 626 | random = self.random |
| 627 | z = self.gauss_next |
| 628 | self.gauss_next = None |
| 629 | if z is None: |
| 630 | x2pi = random() * TWOPI |
| 631 | g2rad = _sqrt(-2.0 * _log(1.0 - random())) |
| 632 | z = _cos(x2pi) * g2rad |
| 633 | self.gauss_next = _sin(x2pi) * g2rad |
Guido van Rossum | cc32ac9 | 1994-03-15 16:10:24 +0000 | [diff] [blame] | 634 | |
Tim Peters | d7b5e88 | 2001-01-25 03:36:26 +0000 | [diff] [blame] | 635 | return mu + z*sigma |
Guido van Rossum | 95bfcda | 1994-03-09 14:21:05 +0000 | [diff] [blame] | 636 | |
Tim Peters | cd80410 | 2001-01-25 20:25:57 +0000 | [diff] [blame] | 637 | ## -------------------- beta -------------------- |
Tim Peters | 85e2e47 | 2001-01-26 06:49:56 +0000 | [diff] [blame] | 638 | ## See |
Ezio Melotti | 20f53f1 | 2011-04-15 08:25:16 +0300 | [diff] [blame] | 639 | ## http://mail.python.org/pipermail/python-bugs-list/2001-January/003752.html |
Tim Peters | 85e2e47 | 2001-01-26 06:49:56 +0000 | [diff] [blame] | 640 | ## for Ivan Frohne's insightful analysis of why the original implementation: |
| 641 | ## |
| 642 | ## def betavariate(self, alpha, beta): |
| 643 | ## # Discrete Event Simulation in C, pp 87-88. |
| 644 | ## |
| 645 | ## y = self.expovariate(alpha) |
| 646 | ## z = self.expovariate(1.0/beta) |
| 647 | ## return z/(y+z) |
| 648 | ## |
| 649 | ## was dead wrong, and how it probably got that way. |
Guido van Rossum | 95bfcda | 1994-03-09 14:21:05 +0000 | [diff] [blame] | 650 | |
Tim Peters | d7b5e88 | 2001-01-25 03:36:26 +0000 | [diff] [blame] | 651 | def betavariate(self, alpha, beta): |
Raymond Hettinger | c32f033 | 2002-05-23 19:44:49 +0000 | [diff] [blame] | 652 | """Beta distribution. |
| 653 | |
Thomas Wouters | b213704 | 2007-02-01 18:02:27 +0000 | [diff] [blame] | 654 | Conditions on the parameters are alpha > 0 and beta > 0. |
Raymond Hettinger | c32f033 | 2002-05-23 19:44:49 +0000 | [diff] [blame] | 655 | Returned values range between 0 and 1. |
Raymond Hettinger | ef4d4bd | 2002-05-23 23:58:17 +0000 | [diff] [blame] | 656 | |
Raymond Hettinger | c32f033 | 2002-05-23 19:44:49 +0000 | [diff] [blame] | 657 | """ |
Raymond Hettinger | ef4d4bd | 2002-05-23 23:58:17 +0000 | [diff] [blame] | 658 | |
Tim Peters | 85e2e47 | 2001-01-26 06:49:56 +0000 | [diff] [blame] | 659 | # This version due to Janne Sinkkonen, and matches all the std |
| 660 | # texts (e.g., Knuth Vol 2 Ed 3 pg 134 "the beta distribution"). |
Raymond Hettinger | 650c1c9 | 2016-06-25 05:36:42 +0300 | [diff] [blame] | 661 | y = self.gammavariate(alpha, 1.0) |
Tim Peters | 85e2e47 | 2001-01-26 06:49:56 +0000 | [diff] [blame] | 662 | if y == 0: |
| 663 | return 0.0 |
| 664 | else: |
Raymond Hettinger | 650c1c9 | 2016-06-25 05:36:42 +0300 | [diff] [blame] | 665 | return y / (y + self.gammavariate(beta, 1.0)) |
Guido van Rossum | 95bfcda | 1994-03-09 14:21:05 +0000 | [diff] [blame] | 666 | |
Tim Peters | cd80410 | 2001-01-25 20:25:57 +0000 | [diff] [blame] | 667 | ## -------------------- Pareto -------------------- |
Guido van Rossum | cf4559a | 1997-12-02 02:47:39 +0000 | [diff] [blame] | 668 | |
Tim Peters | d7b5e88 | 2001-01-25 03:36:26 +0000 | [diff] [blame] | 669 | def paretovariate(self, alpha): |
Raymond Hettinger | c32f033 | 2002-05-23 19:44:49 +0000 | [diff] [blame] | 670 | """Pareto distribution. alpha is the shape parameter.""" |
Tim Peters | d7b5e88 | 2001-01-25 03:36:26 +0000 | [diff] [blame] | 671 | # Jain, pg. 495 |
Guido van Rossum | cf4559a | 1997-12-02 02:47:39 +0000 | [diff] [blame] | 672 | |
Raymond Hettinger | 73ced7e | 2003-01-04 09:26:32 +0000 | [diff] [blame] | 673 | u = 1.0 - self.random() |
Raymond Hettinger | 8ff1099 | 2010-09-08 18:58:33 +0000 | [diff] [blame] | 674 | return 1.0 / u ** (1.0/alpha) |
Guido van Rossum | cf4559a | 1997-12-02 02:47:39 +0000 | [diff] [blame] | 675 | |
Tim Peters | cd80410 | 2001-01-25 20:25:57 +0000 | [diff] [blame] | 676 | ## -------------------- Weibull -------------------- |
Guido van Rossum | cf4559a | 1997-12-02 02:47:39 +0000 | [diff] [blame] | 677 | |
Tim Peters | d7b5e88 | 2001-01-25 03:36:26 +0000 | [diff] [blame] | 678 | def weibullvariate(self, alpha, beta): |
Raymond Hettinger | c32f033 | 2002-05-23 19:44:49 +0000 | [diff] [blame] | 679 | """Weibull distribution. |
| 680 | |
| 681 | alpha is the scale parameter and beta is the shape parameter. |
Raymond Hettinger | ef4d4bd | 2002-05-23 23:58:17 +0000 | [diff] [blame] | 682 | |
Raymond Hettinger | c32f033 | 2002-05-23 19:44:49 +0000 | [diff] [blame] | 683 | """ |
Tim Peters | d7b5e88 | 2001-01-25 03:36:26 +0000 | [diff] [blame] | 684 | # Jain, pg. 499; bug fix courtesy Bill Arms |
Guido van Rossum | cf4559a | 1997-12-02 02:47:39 +0000 | [diff] [blame] | 685 | |
Raymond Hettinger | 73ced7e | 2003-01-04 09:26:32 +0000 | [diff] [blame] | 686 | u = 1.0 - self.random() |
Raymond Hettinger | 183cd1f | 2010-09-08 18:48:21 +0000 | [diff] [blame] | 687 | return alpha * (-_log(u)) ** (1.0/beta) |
Guido van Rossum | 6c395ba | 1999-08-18 13:53:28 +0000 | [diff] [blame] | 688 | |
Raymond Hettinger | 23f1241 | 2004-09-13 22:23:21 +0000 | [diff] [blame] | 689 | ## --------------- Operating System Random Source ------------------ |
Raymond Hettinger | 356a459 | 2004-08-30 06:14:31 +0000 | [diff] [blame] | 690 | |
Raymond Hettinger | 23f1241 | 2004-09-13 22:23:21 +0000 | [diff] [blame] | 691 | class SystemRandom(Random): |
| 692 | """Alternate random number generator using sources provided |
| 693 | by the operating system (such as /dev/urandom on Unix or |
| 694 | CryptGenRandom on Windows). |
Raymond Hettinger | 356a459 | 2004-08-30 06:14:31 +0000 | [diff] [blame] | 695 | |
| 696 | Not available on all systems (see os.urandom() for details). |
| 697 | """ |
| 698 | |
| 699 | def random(self): |
| 700 | """Get the next random number in the range [0.0, 1.0).""" |
Raymond Hettinger | 183cd1f | 2010-09-08 18:48:21 +0000 | [diff] [blame] | 701 | return (int.from_bytes(_urandom(7), 'big') >> 3) * RECIP_BPF |
Raymond Hettinger | 356a459 | 2004-08-30 06:14:31 +0000 | [diff] [blame] | 702 | |
| 703 | def getrandbits(self, k): |
Serhiy Storchaka | 9594942 | 2013-08-27 19:40:23 +0300 | [diff] [blame] | 704 | """getrandbits(k) -> x. Generates an int with k random bits.""" |
Raymond Hettinger | 356a459 | 2004-08-30 06:14:31 +0000 | [diff] [blame] | 705 | if k <= 0: |
| 706 | raise ValueError('number of bits must be greater than zero') |
| 707 | if k != int(k): |
| 708 | raise TypeError('number of bits should be an integer') |
Raymond Hettinger | 63b1767 | 2010-09-08 19:27:59 +0000 | [diff] [blame] | 709 | numbytes = (k + 7) // 8 # bits / 8 and rounded up |
| 710 | x = int.from_bytes(_urandom(numbytes), 'big') |
| 711 | return x >> (numbytes * 8 - k) # trim excess bits |
Raymond Hettinger | 356a459 | 2004-08-30 06:14:31 +0000 | [diff] [blame] | 712 | |
Raymond Hettinger | 28de64f | 2008-01-13 23:40:30 +0000 | [diff] [blame] | 713 | def seed(self, *args, **kwds): |
Raymond Hettinger | 23f1241 | 2004-09-13 22:23:21 +0000 | [diff] [blame] | 714 | "Stub method. Not used for a system random number generator." |
Raymond Hettinger | 356a459 | 2004-08-30 06:14:31 +0000 | [diff] [blame] | 715 | return None |
Raymond Hettinger | 356a459 | 2004-08-30 06:14:31 +0000 | [diff] [blame] | 716 | |
| 717 | def _notimplemented(self, *args, **kwds): |
Raymond Hettinger | 23f1241 | 2004-09-13 22:23:21 +0000 | [diff] [blame] | 718 | "Method should not be called for a system random number generator." |
| 719 | raise NotImplementedError('System entropy source does not have state.') |
Raymond Hettinger | 356a459 | 2004-08-30 06:14:31 +0000 | [diff] [blame] | 720 | getstate = setstate = _notimplemented |
| 721 | |
Tim Peters | cd80410 | 2001-01-25 20:25:57 +0000 | [diff] [blame] | 722 | ## -------------------- test program -------------------- |
Guido van Rossum | ff03b1a | 1994-03-09 12:55:02 +0000 | [diff] [blame] | 723 | |
Raymond Hettinger | 6229713 | 2003-08-30 01:24:19 +0000 | [diff] [blame] | 724 | def _test_generator(n, func, args): |
Tim Peters | 0c9886d | 2001-01-15 01:18:21 +0000 | [diff] [blame] | 725 | import time |
Guido van Rossum | be19ed7 | 2007-02-09 05:37:30 +0000 | [diff] [blame] | 726 | print(n, 'times', func.__name__) |
Raymond Hettinger | b98154e | 2003-05-24 17:26:02 +0000 | [diff] [blame] | 727 | total = 0.0 |
Tim Peters | 0c9886d | 2001-01-15 01:18:21 +0000 | [diff] [blame] | 728 | sqsum = 0.0 |
| 729 | smallest = 1e10 |
| 730 | largest = -1e10 |
| 731 | t0 = time.time() |
| 732 | for i in range(n): |
Raymond Hettinger | 6229713 | 2003-08-30 01:24:19 +0000 | [diff] [blame] | 733 | x = func(*args) |
Raymond Hettinger | b98154e | 2003-05-24 17:26:02 +0000 | [diff] [blame] | 734 | total += x |
Tim Peters | 0c9886d | 2001-01-15 01:18:21 +0000 | [diff] [blame] | 735 | sqsum = sqsum + x*x |
| 736 | smallest = min(x, smallest) |
| 737 | largest = max(x, largest) |
| 738 | t1 = time.time() |
Guido van Rossum | be19ed7 | 2007-02-09 05:37:30 +0000 | [diff] [blame] | 739 | print(round(t1-t0, 3), 'sec,', end=' ') |
Raymond Hettinger | b98154e | 2003-05-24 17:26:02 +0000 | [diff] [blame] | 740 | avg = total/n |
Tim Peters | d7b5e88 | 2001-01-25 03:36:26 +0000 | [diff] [blame] | 741 | stddev = _sqrt(sqsum/n - avg*avg) |
Raymond Hettinger | 1f54814 | 2014-05-19 20:21:43 +0100 | [diff] [blame] | 742 | print('avg %g, stddev %g, min %g, max %g\n' % \ |
Guido van Rossum | be19ed7 | 2007-02-09 05:37:30 +0000 | [diff] [blame] | 743 | (avg, stddev, smallest, largest)) |
Guido van Rossum | ff03b1a | 1994-03-09 12:55:02 +0000 | [diff] [blame] | 744 | |
Raymond Hettinger | f24eb35 | 2002-11-12 17:41:57 +0000 | [diff] [blame] | 745 | |
| 746 | def _test(N=2000): |
Raymond Hettinger | 6229713 | 2003-08-30 01:24:19 +0000 | [diff] [blame] | 747 | _test_generator(N, random, ()) |
| 748 | _test_generator(N, normalvariate, (0.0, 1.0)) |
| 749 | _test_generator(N, lognormvariate, (0.0, 1.0)) |
| 750 | _test_generator(N, vonmisesvariate, (0.0, 1.0)) |
| 751 | _test_generator(N, gammavariate, (0.01, 1.0)) |
| 752 | _test_generator(N, gammavariate, (0.1, 1.0)) |
| 753 | _test_generator(N, gammavariate, (0.1, 2.0)) |
| 754 | _test_generator(N, gammavariate, (0.5, 1.0)) |
| 755 | _test_generator(N, gammavariate, (0.9, 1.0)) |
| 756 | _test_generator(N, gammavariate, (1.0, 1.0)) |
| 757 | _test_generator(N, gammavariate, (2.0, 1.0)) |
| 758 | _test_generator(N, gammavariate, (20.0, 1.0)) |
| 759 | _test_generator(N, gammavariate, (200.0, 1.0)) |
| 760 | _test_generator(N, gauss, (0.0, 1.0)) |
| 761 | _test_generator(N, betavariate, (3.0, 3.0)) |
Christian Heimes | fe337bf | 2008-03-23 21:54:12 +0000 | [diff] [blame] | 762 | _test_generator(N, triangular, (0.0, 1.0, 1.0/3.0)) |
Tim Peters | cd80410 | 2001-01-25 20:25:57 +0000 | [diff] [blame] | 763 | |
Tim Peters | 715c4c4 | 2001-01-26 22:56:56 +0000 | [diff] [blame] | 764 | # Create one instance, seeded from current time, and export its methods |
Raymond Hettinger | 40f6217 | 2002-12-29 23:03:38 +0000 | [diff] [blame] | 765 | # as module-level functions. The functions share state across all uses |
| 766 | #(both in the user's code and in the Python libraries), but that's fine |
| 767 | # for most programs and is easier for the casual user than making them |
| 768 | # instantiate their own Random() instance. |
| 769 | |
Tim Peters | d7b5e88 | 2001-01-25 03:36:26 +0000 | [diff] [blame] | 770 | _inst = Random() |
| 771 | seed = _inst.seed |
| 772 | random = _inst.random |
| 773 | uniform = _inst.uniform |
Christian Heimes | fe337bf | 2008-03-23 21:54:12 +0000 | [diff] [blame] | 774 | triangular = _inst.triangular |
Tim Peters | d7b5e88 | 2001-01-25 03:36:26 +0000 | [diff] [blame] | 775 | randint = _inst.randint |
| 776 | choice = _inst.choice |
| 777 | randrange = _inst.randrange |
Raymond Hettinger | f24eb35 | 2002-11-12 17:41:57 +0000 | [diff] [blame] | 778 | sample = _inst.sample |
Tim Peters | d7b5e88 | 2001-01-25 03:36:26 +0000 | [diff] [blame] | 779 | shuffle = _inst.shuffle |
Raymond Hettinger | 28aa4a0 | 2016-09-07 00:08:44 -0700 | [diff] [blame] | 780 | choices = _inst.choices |
Tim Peters | d7b5e88 | 2001-01-25 03:36:26 +0000 | [diff] [blame] | 781 | normalvariate = _inst.normalvariate |
| 782 | lognormvariate = _inst.lognormvariate |
Tim Peters | d7b5e88 | 2001-01-25 03:36:26 +0000 | [diff] [blame] | 783 | expovariate = _inst.expovariate |
| 784 | vonmisesvariate = _inst.vonmisesvariate |
| 785 | gammavariate = _inst.gammavariate |
Tim Peters | d7b5e88 | 2001-01-25 03:36:26 +0000 | [diff] [blame] | 786 | gauss = _inst.gauss |
| 787 | betavariate = _inst.betavariate |
| 788 | paretovariate = _inst.paretovariate |
| 789 | weibullvariate = _inst.weibullvariate |
| 790 | getstate = _inst.getstate |
| 791 | setstate = _inst.setstate |
Raymond Hettinger | 2f726e9 | 2003-10-05 09:09:15 +0000 | [diff] [blame] | 792 | getrandbits = _inst.getrandbits |
Tim Peters | d7b5e88 | 2001-01-25 03:36:26 +0000 | [diff] [blame] | 793 | |
Antoine Pitrou | 346cbd3 | 2017-05-27 17:50:54 +0200 | [diff] [blame] | 794 | if hasattr(_os, "fork"): |
Gregory P. Smith | 163468a | 2017-05-29 10:03:41 -0700 | [diff] [blame] | 795 | _os.register_at_fork(after_in_child=_inst.seed) |
Antoine Pitrou | 346cbd3 | 2017-05-27 17:50:54 +0200 | [diff] [blame] | 796 | |
| 797 | |
Guido van Rossum | ff03b1a | 1994-03-09 12:55:02 +0000 | [diff] [blame] | 798 | if __name__ == '__main__': |
Tim Peters | d7b5e88 | 2001-01-25 03:36:26 +0000 | [diff] [blame] | 799 | _test() |