import random
class CMWC(random.Random):
'Long period random number generator: Complementary Multiply with Carry'
# http://en.wikipedia.org/wiki/Multiply-with-carry
a = 3636507990
logb = 32
b = 2 ** logb
r = 1359
def _gen_word(self):
i = self.i
xc, self.c = divmod(self.a * self.Q[i] + self.c, self.b)
x = self.Q[i] = self.b - 1 - xc
self.i = 0 if i + 1 == self.r else i + 1
return x
def getrandbits(self, k):
while self.bits < k:
self.f = (self.f << self.logb) | self._gen_word()
self.bits += self.logb
x = self.f & ((1 << k) - 1)
self.f >>= k; self.bits -= k
return x
def random(self, RECIP_BPF=random.RECIP_BPF, BPF=random.BPF):
return self.getrandbits(BPF) * RECIP_BPF
def seed(self, seed=None):
seeder = random.Random(seed)
Q = [seeder.randrange(0x100000000) for i in range(self.r)]
c = seeder.randrange(0x100000000)
self.setstate((0, 0, 0, c, Q))
def getstate(self):
return self.f, self.bits, self.i, self.c, tuple(self.Q)
def setstate(self, (f, bits, i, c, Q)):
self.f, self.bits, self.i, self.c, self.Q = f, bits, i, c, list(Q)
if __name__ == '__main__':
prng = CMWC(134123413541344)
for i in range(20):
print prng.random()
print
for i in range(20):
print normalvariate(mu=5.0, sigma=2.2)
Diff to Previous Revision
--- revision 12 2009-04-01 10:53:27
+++ revision 13 2010-12-02 05:19:25
@@ -36,8 +36,8 @@
def getstate(self):
return self.f, self.bits, self.i, self.c, tuple(self.Q)
- def setstate(self, (bits, f, i, c, Q)):
- self.f, self.bits, self.i, self.c, self.Q = f, bits, i, c, list(Q)
+ def setstate(self, (f, bits, i, c, Q)):
+ self.f, self.bits, self.i, self.c, self.Q = f, bits, i, c, list(Q)
if __name__ == '__main__':
