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843 lines
29 KiB
843 lines
29 KiB
"""Random variable generators. |
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|
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integers |
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-------- |
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uniform within range |
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|
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sequences |
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--------- |
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pick random element |
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pick random sample |
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generate random permutation |
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|
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distributions on the real line: |
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------------------------------ |
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uniform |
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normal (Gaussian) |
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lognormal |
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negative exponential |
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gamma |
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beta |
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pareto |
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Weibull |
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distributions on the circle (angles 0 to 2pi) |
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--------------------------------------------- |
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circular uniform |
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von Mises |
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General notes on the underlying Mersenne Twister core generator: |
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* The period is 2**19937-1. |
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* It is one of the most extensively tested generators in existence |
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* Without a direct way to compute N steps forward, the |
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semantics of jumpahead(n) are weakened to simply jump |
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to another distant state and rely on the large period |
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to avoid overlapping sequences. |
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* The random() method is implemented in C, executes in |
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a single Python step, and is, therefore, threadsafe. |
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""" |
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from types import BuiltinMethodType as _BuiltinMethodType |
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from math import log as _log, exp as _exp, pi as _pi, e as _e |
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from math import sqrt as _sqrt, acos as _acos, cos as _cos, sin as _sin |
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from math import floor as _floor |
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__all__ = ["Random","seed","random","uniform","randint","choice","sample", |
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"randrange","shuffle","normalvariate","lognormvariate", |
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"cunifvariate","expovariate","vonmisesvariate","gammavariate", |
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"stdgamma","gauss","betavariate","paretovariate","weibullvariate", |
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"getstate","setstate","jumpahead", "WichmannHill"] |
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NV_MAGICCONST = 4 * _exp(-0.5)/_sqrt(2.0) |
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TWOPI = 2.0*_pi |
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LOG4 = _log(4.0) |
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SG_MAGICCONST = 1.0 + _log(4.5) |
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BPF = 53 # Number of bits in a float |
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# Translated by Guido van Rossum from C source provided by |
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# Adrian Baddeley. Adapted by Raymond Hettinger for use with |
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# the Mersenne Twister core generator. |
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import _random |
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class Random(_random.Random): |
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"""Random number generator base class used by bound module functions. |
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Used to instantiate instances of Random to get generators that don't |
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share state. Especially useful for multi-threaded programs, creating |
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a different instance of Random for each thread, and using the jumpahead() |
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method to ensure that the generated sequences seen by each thread don't |
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overlap. |
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Class Random can also be subclassed if you want to use a different basic |
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generator of your own devising: in that case, override the following |
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methods: random(), seed(), getstate(), setstate() and jumpahead(). |
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""" |
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VERSION = 2 # used by getstate/setstate |
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def __init__(self, x=None): |
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"""Initialize an instance. |
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Optional argument x controls seeding, as for Random.seed(). |
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""" |
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self.seed(x) |
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self.gauss_next = None |
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def seed(self, a=None): |
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"""Initialize internal state from hashable object. |
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None or no argument seeds from current time. |
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If a is not None or an int or long, hash(a) is used instead. |
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""" |
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if a is None: |
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import time |
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a = long(time.time() * 256) # use fractional seconds |
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super(Random, self).seed(a) |
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self.gauss_next = None |
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def getstate(self): |
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"""Return internal state; can be passed to setstate() later.""" |
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return self.VERSION, super(Random, self).getstate(), self.gauss_next |
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def setstate(self, state): |
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"""Restore internal state from object returned by getstate().""" |
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version = state[0] |
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if version == 2: |
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version, internalstate, self.gauss_next = state |
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super(Random, self).setstate(internalstate) |
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else: |
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raise ValueError("state with version %s passed to " |
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"Random.setstate() of version %s" % |
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(version, self.VERSION)) |
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## ---- Methods below this point do not need to be overridden when |
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## ---- subclassing for the purpose of using a different core generator. |
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## -------------------- pickle support ------------------- |
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def __getstate__(self): # for pickle |
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return self.getstate() |
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def __setstate__(self, state): # for pickle |
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self.setstate(state) |
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def __reduce__(self): |
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return self.__class__, (), self.getstate() |
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|
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## -------------------- integer methods ------------------- |
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def randrange(self, start, stop=None, step=1, int=int, default=None, |
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maxwidth=1L<<BPF, _BuiltinMethod=_BuiltinMethodType): |
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"""Choose a random item from range(start, stop[, step]). |
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This fixes the problem with randint() which includes the |
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endpoint; in Python this is usually not what you want. |
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Do not supply the 'int', 'default', and 'maxwidth' arguments. |
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""" |
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# This code is a bit messy to make it fast for the |
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# common case while still doing adequate error checking. |
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istart = int(start) |
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if istart != start: |
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raise ValueError, "non-integer arg 1 for randrange()" |
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if stop is default: |
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if istart > 0: |
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if istart >= maxwidth and type(self.random) is _BuiltinMethod: |
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return self._randbelow(istart) |
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return int(self.random() * istart) |
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raise ValueError, "empty range for randrange()" |
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# stop argument supplied. |
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istop = int(stop) |
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if istop != stop: |
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raise ValueError, "non-integer stop for randrange()" |
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width = istop - istart |
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if step == 1 and width > 0: |
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# Note that |
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# int(istart + self.random()*(istop - istart)) |
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# instead would be incorrect. For example, consider istart |
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# = -2 and istop = 0. Then the guts would be in |
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# -2.0 to 0.0 exclusive on both ends (ignoring that random() |
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# might return 0.0), and because int() truncates toward 0, the |
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# final result would be -1 or 0 (instead of -2 or -1). |
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# istart + int(self.random()*(istop - istart)) |
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# would also be incorrect, for a subtler reason: the RHS |
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# can return a long, and then randrange() would also return |
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# a long, but we're supposed to return an int (for backward |
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# compatibility). |
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if width >= maxwidth and type(self.random) is _BuiltinMethod: |
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return int(istart + self._randbelow(width)) |
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return int(istart + int(self.random()*width)) |
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if step == 1: |
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raise ValueError, "empty range for randrange()" |
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# Non-unit step argument supplied. |
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istep = int(step) |
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if istep != step: |
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raise ValueError, "non-integer step for randrange()" |
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if istep > 0: |
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n = (width + istep - 1) / istep |
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elif istep < 0: |
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n = (width + istep + 1) / istep |
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else: |
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raise ValueError, "zero step for randrange()" |
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if n <= 0: |
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raise ValueError, "empty range for randrange()" |
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if n >= maxwidth and type(self.random) is _BuiltinMethod: |
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return istart + self._randbelow(n) |
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return istart + istep*int(self.random() * n) |
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def randint(self, a, b): |
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"""Return random integer in range [a, b], including both end points. |
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""" |
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return self.randrange(a, b+1) |
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def _randbelow(self, n, bpf=BPF, maxwidth=1L<<BPF, |
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long=long, _log=_log, int=int): |
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"""Return a random int in the range [0,n) |
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Handles the case where n has more bits than returned |
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by a single call to the underlying generator. |
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""" |
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# k is a sometimes over but never under estimate of the bits in n |
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k = int(1.00001 + _log(n-1, 2)) # 2**k > n-1 >= 2**(k-2) |
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random = self.random |
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r = n |
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while r >= n: |
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# In Py2.4, this section becomes: r = self.getrandbits(k) |
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r = long(random() * maxwidth) |
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bits = bpf |
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while bits < k: |
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r = (r << bpf) | (long(random() * maxwidth)) |
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bits += bpf |
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r >>= (bits - k) |
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return r |
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## -------------------- sequence methods ------------------- |
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def choice(self, seq): |
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"""Choose a random element from a non-empty sequence.""" |
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return seq[int(self.random() * len(seq))] |
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def shuffle(self, x, random=None, int=int): |
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"""x, random=random.random -> shuffle list x in place; return None. |
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Optional arg random is a 0-argument function returning a random |
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float in [0.0, 1.0); by default, the standard random.random. |
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Note that for even rather small len(x), the total number of |
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permutations of x is larger than the period of most random number |
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generators; this implies that "most" permutations of a long |
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sequence can never be generated. |
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""" |
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if random is None: |
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random = self.random |
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for i in xrange(len(x)-1, 0, -1): |
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# pick an element in x[:i+1] with which to exchange x[i] |
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j = int(random() * (i+1)) |
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x[i], x[j] = x[j], x[i] |
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def sample(self, population, k): |
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"""Chooses k unique random elements from a population sequence. |
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Returns a new list containing elements from the population while |
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leaving the original population unchanged. The resulting list is |
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in selection order so that all sub-slices will also be valid random |
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samples. This allows raffle winners (the sample) to be partitioned |
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into grand prize and second place winners (the subslices). |
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Members of the population need not be hashable or unique. If the |
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population contains repeats, then each occurrence is a possible |
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selection in the sample. |
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To choose a sample in a range of integers, use xrange as an argument. |
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This is especially fast and space efficient for sampling from a |
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large population: sample(xrange(10000000), 60) |
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""" |
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# Sampling without replacement entails tracking either potential |
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# selections (the pool) in a list or previous selections in a |
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# dictionary. |
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# When the number of selections is small compared to the population, |
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# then tracking selections is efficient, requiring only a small |
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# dictionary and an occasional reselection. For a larger number of |
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# selections, the pool tracking method is preferred since the list takes |
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# less space than the dictionary and it doesn't suffer from frequent |
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# reselections. |
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n = len(population) |
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if not 0 <= k <= n: |
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raise ValueError, "sample larger than population" |
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random = self.random |
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_int = int |
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result = [None] * k |
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if n < 6 * k: # if n len list takes less space than a k len dict |
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pool = list(population) |
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for i in xrange(k): # invariant: non-selected at [0,n-i) |
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j = _int(random() * (n-i)) |
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result[i] = pool[j] |
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pool[j] = pool[n-i-1] # move non-selected item into vacancy |
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else: |
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try: |
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n > 0 and (population[0], population[n//2], population[n-1]) |
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except (TypeError, KeyError): # handle sets and dictionaries |
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population = tuple(population) |
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selected = {} |
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for i in xrange(k): |
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j = _int(random() * n) |
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while j in selected: |
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j = _int(random() * n) |
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result[i] = selected[j] = population[j] |
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return result |
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## -------------------- real-valued distributions ------------------- |
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## -------------------- uniform distribution ------------------- |
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def uniform(self, a, b): |
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"""Get a random number in the range [a, b).""" |
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return a + (b-a) * self.random() |
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## -------------------- normal distribution -------------------- |
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def normalvariate(self, mu, sigma): |
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"""Normal distribution. |
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mu is the mean, and sigma is the standard deviation. |
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""" |
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# mu = mean, sigma = standard deviation |
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# Uses Kinderman and Monahan method. Reference: Kinderman, |
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# A.J. and Monahan, J.F., "Computer generation of random |
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# variables using the ratio of uniform deviates", ACM Trans |
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# Math Software, 3, (1977), pp257-260. |
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random = self.random |
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while True: |
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u1 = random() |
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u2 = 1.0 - random() |
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z = NV_MAGICCONST*(u1-0.5)/u2 |
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zz = z*z/4.0 |
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if zz <= -_log(u2): |
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break |
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return mu + z*sigma |
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## -------------------- lognormal distribution -------------------- |
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def lognormvariate(self, mu, sigma): |
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"""Log normal distribution. |
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If you take the natural logarithm of this distribution, you'll get a |
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normal distribution with mean mu and standard deviation sigma. |
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mu can have any value, and sigma must be greater than zero. |
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""" |
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return _exp(self.normalvariate(mu, sigma)) |
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## -------------------- circular uniform -------------------- |
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def cunifvariate(self, mean, arc): |
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"""Circular uniform distribution. |
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mean is the mean angle, and arc is the range of the distribution, |
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centered around the mean angle. Both values must be expressed in |
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radians. Returned values range between mean - arc/2 and |
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mean + arc/2 and are normalized to between 0 and pi. |
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Deprecated in version 2.3. Use: |
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(mean + arc * (Random.random() - 0.5)) % Math.pi |
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""" |
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# mean: mean angle (in radians between 0 and pi) |
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# arc: range of distribution (in radians between 0 and pi) |
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import warnings |
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warnings.warn("The cunifvariate function is deprecated; Use (mean " |
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"+ arc * (Random.random() - 0.5)) % Math.pi instead.", |
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DeprecationWarning, 2) |
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return (mean + arc * (self.random() - 0.5)) % _pi |
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## -------------------- exponential distribution -------------------- |
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def expovariate(self, lambd): |
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"""Exponential distribution. |
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lambd is 1.0 divided by the desired mean. (The parameter would be |
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called "lambda", but that is a reserved word in Python.) Returned |
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values range from 0 to positive infinity. |
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""" |
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# lambd: rate lambd = 1/mean |
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# ('lambda' is a Python reserved word) |
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random = self.random |
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u = random() |
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while u <= 1e-7: |
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u = random() |
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return -_log(u)/lambd |
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|
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## -------------------- von Mises distribution -------------------- |
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def vonmisesvariate(self, mu, kappa): |
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"""Circular data distribution. |
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mu is the mean angle, expressed in radians between 0 and 2*pi, and |
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kappa is the concentration parameter, which must be greater than or |
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equal to zero. If kappa is equal to zero, this distribution reduces |
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to a uniform random angle over the range 0 to 2*pi. |
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""" |
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# mu: mean angle (in radians between 0 and 2*pi) |
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# kappa: concentration parameter kappa (>= 0) |
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# if kappa = 0 generate uniform random angle |
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# Based upon an algorithm published in: Fisher, N.I., |
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# "Statistical Analysis of Circular Data", Cambridge |
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# University Press, 1993. |
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# Thanks to Magnus Kessler for a correction to the |
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# implementation of step 4. |
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random = self.random |
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if kappa <= 1e-6: |
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return TWOPI * random() |
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a = 1.0 + _sqrt(1.0 + 4.0 * kappa * kappa) |
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b = (a - _sqrt(2.0 * a))/(2.0 * kappa) |
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r = (1.0 + b * b)/(2.0 * b) |
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while True: |
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u1 = random() |
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z = _cos(_pi * u1) |
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f = (1.0 + r * z)/(r + z) |
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c = kappa * (r - f) |
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u2 = random() |
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if not (u2 >= c * (2.0 - c) and u2 > c * _exp(1.0 - c)): |
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break |
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u3 = random() |
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if u3 > 0.5: |
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theta = (mu % TWOPI) + _acos(f) |
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else: |
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theta = (mu % TWOPI) - _acos(f) |
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return theta |
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|
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## -------------------- gamma distribution -------------------- |
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def gammavariate(self, alpha, beta): |
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"""Gamma distribution. Not the gamma function! |
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Conditions on the parameters are alpha > 0 and beta > 0. |
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""" |
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# alpha > 0, beta > 0, mean is alpha*beta, variance is alpha*beta**2 |
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# Warning: a few older sources define the gamma distribution in terms |
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# of alpha > -1.0 |
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if alpha <= 0.0 or beta <= 0.0: |
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raise ValueError, 'gammavariate: alpha and beta must be > 0.0' |
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random = self.random |
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if alpha > 1.0: |
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# Uses R.C.H. Cheng, "The generation of Gamma |
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# variables with non-integral shape parameters", |
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# Applied Statistics, (1977), 26, No. 1, p71-74 |
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ainv = _sqrt(2.0 * alpha - 1.0) |
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bbb = alpha - LOG4 |
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ccc = alpha + ainv |
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while True: |
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u1 = random() |
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if not 1e-7 < u1 < .9999999: |
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continue |
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u2 = 1.0 - random() |
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v = _log(u1/(1.0-u1))/ainv |
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x = alpha*_exp(v) |
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z = u1*u1*u2 |
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r = bbb+ccc*v-x |
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if r + SG_MAGICCONST - 4.5*z >= 0.0 or r >= _log(z): |
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return x * beta |
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|
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elif alpha == 1.0: |
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# expovariate(1) |
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u = random() |
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while u <= 1e-7: |
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u = random() |
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return -_log(u) * beta |
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else: # alpha is between 0 and 1 (exclusive) |
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# Uses ALGORITHM GS of Statistical Computing - Kennedy & Gentle |
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while True: |
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u = random() |
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b = (_e + alpha)/_e |
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p = b*u |
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if p <= 1.0: |
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x = pow(p, 1.0/alpha) |
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else: |
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# p > 1 |
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x = -_log((b-p)/alpha) |
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u1 = random() |
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if not (((p <= 1.0) and (u1 > _exp(-x))) or |
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((p > 1) and (u1 > pow(x, alpha - 1.0)))): |
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break |
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return x * beta |
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def stdgamma(self, alpha, ainv, bbb, ccc): |
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# This method was (and shall remain) undocumented. |
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# This method is deprecated |
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# for the following reasons: |
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# 1. Returns same as .gammavariate(alpha, 1.0) |
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# 2. Requires caller to provide 3 extra arguments |
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# that are functions of alpha anyway |
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# 3. Can't be used for alpha < 0.5 |
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# ainv = sqrt(2 * alpha - 1) |
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# bbb = alpha - log(4) |
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# ccc = alpha + ainv |
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import warnings |
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warnings.warn("The stdgamma function is deprecated; " |
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"use gammavariate() instead.", |
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DeprecationWarning, 2) |
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return self.gammavariate(alpha, 1.0) |
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## -------------------- Gauss (faster alternative) -------------------- |
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def gauss(self, mu, sigma): |
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"""Gaussian distribution. |
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mu is the mean, and sigma is the standard deviation. This is |
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slightly faster than the normalvariate() function. |
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Not thread-safe without a lock around calls. |
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|
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""" |
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# When x and y are two variables from [0, 1), uniformly |
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# distributed, then |
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# |
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# cos(2*pi*x)*sqrt(-2*log(1-y)) |
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# sin(2*pi*x)*sqrt(-2*log(1-y)) |
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# |
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# are two *independent* variables with normal distribution |
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# (mu = 0, sigma = 1). |
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# (Lambert Meertens) |
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# (corrected version; bug discovered by Mike Miller, fixed by LM) |
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|
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# Multithreading note: When two threads call this function |
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# simultaneously, it is possible that they will receive the |
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# same return value. The window is very small though. To |
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# avoid this, you have to use a lock around all calls. (I |
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# didn't want to slow this down in the serial case by using a |
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# lock here.) |
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random = self.random |
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z = self.gauss_next |
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self.gauss_next = None |
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if z is None: |
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x2pi = random() * TWOPI |
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g2rad = _sqrt(-2.0 * _log(1.0 - random())) |
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z = _cos(x2pi) * g2rad |
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self.gauss_next = _sin(x2pi) * g2rad |
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return mu + z*sigma |
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|
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## -------------------- beta -------------------- |
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## See |
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## http://sourceforge.net/bugs/?func=detailbug&bug_id=130030&group_id=5470 |
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## for Ivan Frohne's insightful analysis of why the original implementation: |
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## |
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## def betavariate(self, alpha, beta): |
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## # Discrete Event Simulation in C, pp 87-88. |
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## |
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## y = self.expovariate(alpha) |
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## z = self.expovariate(1.0/beta) |
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## return z/(y+z) |
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## |
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## was dead wrong, and how it probably got that way. |
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|
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def betavariate(self, alpha, beta): |
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"""Beta distribution. |
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Conditions on the parameters are alpha > -1 and beta} > -1. |
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Returned values range between 0 and 1. |
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""" |
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# This version due to Janne Sinkkonen, and matches all the std |
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# texts (e.g., Knuth Vol 2 Ed 3 pg 134 "the beta distribution"). |
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y = self.gammavariate(alpha, 1.) |
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if y == 0: |
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return 0.0 |
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else: |
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return y / (y + self.gammavariate(beta, 1.)) |
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|
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## -------------------- Pareto -------------------- |
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def paretovariate(self, alpha): |
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"""Pareto distribution. alpha is the shape parameter.""" |
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# Jain, pg. 495 |
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u = 1.0 - self.random() |
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return 1.0 / pow(u, 1.0/alpha) |
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## -------------------- Weibull -------------------- |
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def weibullvariate(self, alpha, beta): |
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"""Weibull distribution. |
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alpha is the scale parameter and beta is the shape parameter. |
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""" |
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# Jain, pg. 499; bug fix courtesy Bill Arms |
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u = 1.0 - self.random() |
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return alpha * pow(-_log(u), 1.0/beta) |
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|
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## -------------------- Wichmann-Hill ------------------- |
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class WichmannHill(Random): |
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VERSION = 1 # used by getstate/setstate |
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def seed(self, a=None): |
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"""Initialize internal state from hashable object. |
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None or no argument seeds from current time. |
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If a is not None or an int or long, hash(a) is used instead. |
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If a is an int or long, a is used directly. Distinct values between |
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0 and 27814431486575L inclusive are guaranteed to yield distinct |
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internal states (this guarantee is specific to the default |
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Wichmann-Hill generator). |
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""" |
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if a is None: |
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# Initialize from current time |
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import time |
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a = long(time.time() * 256) |
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if not isinstance(a, (int, long)): |
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a = hash(a) |
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a, x = divmod(a, 30268) |
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a, y = divmod(a, 30306) |
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a, z = divmod(a, 30322) |
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self._seed = int(x)+1, int(y)+1, int(z)+1 |
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self.gauss_next = None |
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def random(self): |
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"""Get the next random number in the range [0.0, 1.0).""" |
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|
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# Wichman-Hill random number generator. |
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# |
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# Wichmann, B. A. & Hill, I. D. (1982) |
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# Algorithm AS 183: |
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# An efficient and portable pseudo-random number generator |
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# Applied Statistics 31 (1982) 188-190 |
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# |
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# see also: |
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# Correction to Algorithm AS 183 |
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# Applied Statistics 33 (1984) 123 |
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# |
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# McLeod, A. I. (1985) |
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# A remark on Algorithm AS 183 |
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# Applied Statistics 34 (1985),198-200 |
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|
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# This part is thread-unsafe: |
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# BEGIN CRITICAL SECTION |
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x, y, z = self._seed |
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x = (171 * x) % 30269 |
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y = (172 * y) % 30307 |
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z = (170 * z) % 30323 |
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self._seed = x, y, z |
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# END CRITICAL SECTION |
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# Note: on a platform using IEEE-754 double arithmetic, this can |
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# never return 0.0 (asserted by Tim; proof too long for a comment). |
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return (x/30269.0 + y/30307.0 + z/30323.0) % 1.0 |
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|
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def getstate(self): |
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"""Return internal state; can be passed to setstate() later.""" |
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return self.VERSION, self._seed, self.gauss_next |
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def setstate(self, state): |
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"""Restore internal state from object returned by getstate().""" |
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version = state[0] |
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if version == 1: |
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version, self._seed, self.gauss_next = state |
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else: |
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raise ValueError("state with version %s passed to " |
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"Random.setstate() of version %s" % |
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(version, self.VERSION)) |
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def jumpahead(self, n): |
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"""Act as if n calls to random() were made, but quickly. |
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n is an int, greater than or equal to 0. |
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|
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Example use: If you have 2 threads and know that each will |
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consume no more than a million random numbers, create two Random |
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objects r1 and r2, then do |
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r2.setstate(r1.getstate()) |
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r2.jumpahead(1000000) |
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Then r1 and r2 will use guaranteed-disjoint segments of the full |
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period. |
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""" |
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|
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if not n >= 0: |
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raise ValueError("n must be >= 0") |
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x, y, z = self._seed |
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x = int(x * pow(171, n, 30269)) % 30269 |
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y = int(y * pow(172, n, 30307)) % 30307 |
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z = int(z * pow(170, n, 30323)) % 30323 |
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self._seed = x, y, z |
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def __whseed(self, x=0, y=0, z=0): |
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"""Set the Wichmann-Hill seed from (x, y, z). |
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These must be integers in the range [0, 256). |
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""" |
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if not type(x) == type(y) == type(z) == int: |
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raise TypeError('seeds must be integers') |
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if not (0 <= x < 256 and 0 <= y < 256 and 0 <= z < 256): |
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raise ValueError('seeds must be in range(0, 256)') |
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if 0 == x == y == z: |
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# Initialize from current time |
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import time |
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t = long(time.time() * 256) |
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t = int((t&0xffffff) ^ (t>>24)) |
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t, x = divmod(t, 256) |
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t, y = divmod(t, 256) |
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t, z = divmod(t, 256) |
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# Zero is a poor seed, so substitute 1 |
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self._seed = (x or 1, y or 1, z or 1) |
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|
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self.gauss_next = None |
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|
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def whseed(self, a=None): |
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"""Seed from hashable object's hash code. |
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None or no argument seeds from current time. It is not guaranteed |
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that objects with distinct hash codes lead to distinct internal |
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states. |
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|
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This is obsolete, provided for compatibility with the seed routine |
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used prior to Python 2.1. Use the .seed() method instead. |
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""" |
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|
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if a is None: |
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self.__whseed() |
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return |
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a = hash(a) |
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a, x = divmod(a, 256) |
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a, y = divmod(a, 256) |
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a, z = divmod(a, 256) |
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x = (x + a) % 256 or 1 |
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y = (y + a) % 256 or 1 |
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z = (z + a) % 256 or 1 |
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self.__whseed(x, y, z) |
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|
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## -------------------- test program -------------------- |
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|
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def _test_generator(n, funccall): |
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import time |
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print n, 'times', funccall |
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code = compile(funccall, funccall, 'eval') |
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total = 0.0 |
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sqsum = 0.0 |
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smallest = 1e10 |
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largest = -1e10 |
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t0 = time.time() |
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for i in range(n): |
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x = eval(code) |
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total += x |
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sqsum = sqsum + x*x |
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smallest = min(x, smallest) |
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largest = max(x, largest) |
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t1 = time.time() |
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print round(t1-t0, 3), 'sec,', |
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avg = total/n |
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stddev = _sqrt(sqsum/n - avg*avg) |
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print 'avg %g, stddev %g, min %g, max %g' % \ |
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(avg, stddev, smallest, largest) |
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|
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def _test(N=2000): |
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_test_generator(N, 'random()') |
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_test_generator(N, 'normalvariate(0.0, 1.0)') |
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_test_generator(N, 'lognormvariate(0.0, 1.0)') |
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_test_generator(N, 'cunifvariate(0.0, 1.0)') |
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_test_generator(N, 'vonmisesvariate(0.0, 1.0)') |
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_test_generator(N, 'gammavariate(0.01, 1.0)') |
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_test_generator(N, 'gammavariate(0.1, 1.0)') |
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_test_generator(N, 'gammavariate(0.1, 2.0)') |
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_test_generator(N, 'gammavariate(0.5, 1.0)') |
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_test_generator(N, 'gammavariate(0.9, 1.0)') |
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_test_generator(N, 'gammavariate(1.0, 1.0)') |
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_test_generator(N, 'gammavariate(2.0, 1.0)') |
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_test_generator(N, 'gammavariate(20.0, 1.0)') |
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_test_generator(N, 'gammavariate(200.0, 1.0)') |
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_test_generator(N, 'gauss(0.0, 1.0)') |
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_test_generator(N, 'betavariate(3.0, 3.0)') |
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|
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# Create one instance, seeded from current time, and export its methods |
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# as module-level functions. The functions share state across all uses |
|
#(both in the user's code and in the Python libraries), but that's fine |
|
# for most programs and is easier for the casual user than making them |
|
# instantiate their own Random() instance. |
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|
|
_inst = Random() |
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seed = _inst.seed |
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random = _inst.random |
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uniform = _inst.uniform |
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randint = _inst.randint |
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choice = _inst.choice |
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randrange = _inst.randrange |
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sample = _inst.sample |
|
shuffle = _inst.shuffle |
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normalvariate = _inst.normalvariate |
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lognormvariate = _inst.lognormvariate |
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cunifvariate = _inst.cunifvariate |
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expovariate = _inst.expovariate |
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vonmisesvariate = _inst.vonmisesvariate |
|
gammavariate = _inst.gammavariate |
|
stdgamma = _inst.stdgamma |
|
gauss = _inst.gauss |
|
betavariate = _inst.betavariate |
|
paretovariate = _inst.paretovariate |
|
weibullvariate = _inst.weibullvariate |
|
getstate = _inst.getstate |
|
setstate = _inst.setstate |
|
jumpahead = _inst.jumpahead |
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|
|
if __name__ == '__main__': |
|
_test()
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