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Gilles Sadowski commented on RNG-122: ------------------------------------- bq. It is more a point of why use a generator that has been superceded? That's a good reason in itself. I assumed that it was done already; sorry for the noise. > Change SeedFactory random source > -------------------------------- > > Key: RNG-122 > URL: https://issues.apache.org/jira/browse/RNG-122 > Project: Commons RNG > Issue Type: Improvement > Components: simple > Affects Versions: 1.3 > Reporter: Alex Herbert > Assignee: Alex Herbert > Priority: Trivial > > The SeedFactory uses {{XOR_SHIFT_1024_S}}. This has a systematic failure in > BigCrush using the lower 32-bit bit in reverse order: > [Xorshift1024*, xorshift1024+, xorshift128+ and xoroshiro128+ fail > statistical tests for > linearity|https://www.sciencedirect.com/science/article/pii/S0377042718306265?dgcid=author] > I have tested {{XOR_SHIFT_1024_S}} and {{XOR_SHIFT_1024_S_PHI}} using 10 runs > of BigCrush and see the following results: > {noformat} > RNG Bit-reversed TestU01 (BigCrush) > XOR_SHIFT_1024_S true 1,2,1,1,1,1,2,2,1,1 > XOR_SHIFT_1024_S_PHI true 1,1,1,1,2,1,1,1,1,1 > RandomSource,Bit-reversed,Test,Failures,Failed > XOR_SHIFT_1024_S,true,TestU01 (BigCrush),1,80 LinearComp, r = 0 > XOR_SHIFT_1024_S,true,TestU01 (BigCrush),1,80 LinearComp, r = 0 > XOR_SHIFT_1024_S,true,TestU01 (BigCrush),1,80 LinearComp, r = 0 > XOR_SHIFT_1024_S,true,TestU01 (BigCrush),1,80 LinearComp, r = 0 > XOR_SHIFT_1024_S,true,TestU01 (BigCrush),1,80 LinearComp, r = 0 > XOR_SHIFT_1024_S,true,TestU01 (BigCrush),1,80 LinearComp, r = 0 > XOR_SHIFT_1024_S,true,TestU01 (BigCrush),1,80 LinearComp, r = 0 > XOR_SHIFT_1024_S,true,TestU01 (BigCrush),2,68 MatrixRank, L=1000, r=0|80 > LinearComp, r = 0 > XOR_SHIFT_1024_S,true,TestU01 (BigCrush),2,25 ClosePairs mNP2S, t = 16|80 > LinearComp, r = 0 > XOR_SHIFT_1024_S,true,TestU01 (BigCrush),2,74 RandomWalk1 M (L=50, r=0)|80 > LinearComp, r = 0 > XOR_SHIFT_1024_S_PHI,true,TestU01 (BigCrush),1,80 LinearComp, r = 0 > XOR_SHIFT_1024_S_PHI,true,TestU01 (BigCrush),1,80 LinearComp, r = 0 > XOR_SHIFT_1024_S_PHI,true,TestU01 (BigCrush),1,80 LinearComp, r = 0 > XOR_SHIFT_1024_S_PHI,true,TestU01 (BigCrush),1,80 LinearComp, r = 0 > XOR_SHIFT_1024_S_PHI,true,TestU01 (BigCrush),1,80 LinearComp, r = 0 > XOR_SHIFT_1024_S_PHI,true,TestU01 (BigCrush),1,80 LinearComp, r = 0 > XOR_SHIFT_1024_S_PHI,true,TestU01 (BigCrush),1,80 LinearComp, r = 0 > XOR_SHIFT_1024_S_PHI,true,TestU01 (BigCrush),1,80 LinearComp, r = 0 > XOR_SHIFT_1024_S_PHI,true,TestU01 (BigCrush),1,80 LinearComp, r = 0 > XOR_SHIFT_1024_S_PHI,true,TestU01 (BigCrush),2,80 LinearComp, r = 0|80 > LinearComp, r = 0 > {noformat} > This shows a systematic failure of the {{LinearComp}} test as observed in the > paper linked above. > Update the SeedFactory to use a different generator. -- This message was sent by Atlassian Jira (v8.3.4#803005)