Created
January 27, 2015 06:46
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pcg32 in python, see http://www.pcg-random.org/
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import pcg32 | |
# make a generator | |
# must seed | |
rng = pcg32.rng() | |
pcg32.srandom_r(rng, 42, 52) | |
for i in range(16): | |
print pcg32.random_r(rng) | |
# or use it global | |
# must seed | |
pcg32.srandom(42, 52) | |
for i in range(16): | |
print pcg32.random() |
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def _uint32(n): | |
return n & 0xffffffff | |
def _uint64(n): | |
return n & 0xffffffffffffffff | |
def rng(state=0, inc=0): | |
return { | |
'state': _uint64(state), | |
'inc': _uint64(inc) | |
} | |
_pcg32_global = rng(0x853c49e6748fea9b, 0xda3e39cb94b95bdb) | |
def srandom_r(rng, initstate, initseq): | |
initstate = _uint64(initstate) | |
initseq = _uint64(initseq) | |
rng['state'] = 0 | |
rng['inc'] = _uint64(initseq << 1) | 1 | |
random_r(rng) | |
rng['state'] = _uint64(rng['state'] + initstate) | |
random_r(rng) | |
def srandom(seed, seq): | |
srandom_r(_pcg32_global, seed, seq) | |
def random_r(rng): | |
oldstate = rng['state'] | |
rng['state'] = _uint64(oldstate * 6364136223846793005 + rng['inc']) | |
xorshifted = _uint32(((oldstate >> 18) ^ oldstate) >> 27) | |
rot = _uint32(oldstate >> 59) | |
return _uint32((xorshifted >> rot) | (xorshifted << ((-rot) & 31))) | |
def random(): | |
return random_r(_pcg32_global) |
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