I'm trying to do the Dieharder Suite tests on my linear congruential generator.
I am not sure if the tests are performed on my generator or simply the results are so weak.
I generate 2,5 mio lines with the generator save them to file testrands.txt with this header:
#==================================================================
# generator lcg seed = 1
#==================================================================
type: d
count: 100000
numbit: 32
1015568748
1586005467
2165703038
3027450565
217083232
1587069247
......
I followed this instruction (as in EXAMPLE)
Then I used the Dieharder suite to carry out the tests in the following way:
dieharder -g 202 -f testrands.txt -a
now the results are surprisingly weak (maybe I have generated too few numbers?)
I do as it is in the guide but still seems to be something not as it should - LCG passes a birthday-spacing (I think it should not) and the remaining results are surprisingly weak
My LCG:
import numpy as np
class LCG(object):
UZERO: np.uint32 = np.uint32(0)
UONE : np.uint32 = np.uint32(1)
def __init__(self, seed: np.uint32, a: np.uint32, c: np.uint32) -> None:
self._seed: np.uint32 = np.uint32(seed)
self._a : np.uint32 = np.uint32(a)
self._c : np.uint32 = np.uint32(c)
def next(self) -> np.uint32:
self._seed = self._a * self._seed + self._c
return self._seed
def seed(self) -> np.uint32:
return self._seed
def set_seed(self, seed: np.uint32) -> np.uint32:
self._seed = seed
def skip(self, ns: np.int32) -> None:
"""
Signed argument - skip forward as well as backward
The algorithm here to determine the parameters used to skip ahead is
described in the paper F. Brown, "Random Number Generation with Arbitrary Stride,"
Trans. Am. Nucl. Soc. (Nov. 1994). This algorithm is able to skip ahead in
O(log2(N)) operations instead of O(N). It computes parameters
A and C which can then be used to find x_N = A*x_0 + C mod 2^M.
"""
nskip: np.uint32 = np.uint32(ns)
a: np.uint32 = self._a
c: np.uint32 = self._c
a_next: np.uint32 = LCG.UONE
c_next: np.uint32 = LCG.UZERO
while nskip > LCG.UZERO:
if (nskip & LCG.UONE) != LCG.UZERO:
a_next = a_next * a
c_next = c_next * a + c
c = (a + LCG.UONE) * c
a = a * a
nskip = nskip >> LCG.UONE
self._seed = a_next * self._seed + c_next
#%%
np.seterr(over='ignore')
a = np.uint32(1664525)
c = np.uint32(1013904223)
seed = np.uint32(1)
rng = LCG(seed, a, c)
q = [rng.next() for _ in range(0, 2500000)]
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