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Note that I'd consider this PR strictly optional. I think that switching algorithms is probably not necessary, but simply possible to be on the safe side. |
The authors of the previously-used xorshift128+ implementation suggest, in the reference source, to move to xoroshiro128+. The comments in that implementation mention some caveats about the fidelity of the lower bits and outputs beyond 5TB. So out of an absolute overabundance of caution one could switch to xoroshiro128++ instead of xoroshiro128+, which is slightly slower. However it seems that this would not justify the slight increase in runtime. With a modified example.c running a _large_ number of iterations before printing, xoroshiro128++ seems slightly slower, while xoroshiro128+ and xorshift128+ are about the same speed (accuracy is ~0.5sec in each case): $ ./build.sh && time ./example # xorshift128+ Generated 100000000 iterations. Last UUID: a078c6b1-bd15-4018-8015-59ef66925a55 ./example 11.33s user 0.00s system 99% cpu 11.372 total $ ./build.sh && time ./example # xoroshiro128+ Generated 100000000 iterations. Last UUID: 0ab70d5e-0156-4830-a663-2e4fef1a45d6 ./example 11.58s user 0.00s system 99% cpu 11.631 total $ ./build.sh && time ./example # xoroshiro128++ Generated 100000000 iterations. Last UUID: 450d0a68-143b-45db-9d72-5c12125277c7 ./example 12.45s user 0.00s system 99% cpu 12.499 total
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The authors of the previously-used
xorshift128+implementation suggest, in the reference source, to move toxoroshiro128+. The comments in that implementation mention some caveats about the fidelity of the lower bits and outputs beyond 5TB. So out of an absolute overabundance of caution one could switch toxoroshiro128++instead ofxoroshiro128+, which is slightly slower.However it seems that this would not justify the slight increase in runtime. With a modified example.c running a large number of iterations before printing,
xoroshiro128++seems slightly slower, whilexoroshiro128+andxorshift128+are about the same speed (accuracy is ~0.5sec in each case):