In a post in the "Gnubg on MacOS High Sierra", I mentionned that I had
noticed a problem with evaluations when built with gcc 7 and using SIMD
instructions but only on FreeBSD.
My recollection was not too accurate. In fact the issue is only with
AVX and probably on all operating systems.
A quick way to check is to run this from the CLI :
set evaluation chequerplay eval plies 0
set gnubgid 4HPwATDgc/ABMA:cIklAAAAAAAE
hint
I get the following results. Even if it is not obvious that a 0.2 equity
is a bit high, it is clear that 24/20 cannot be that close to best.
FreeBSD 11, gcc 7.2.0, AVX
CentOS 6, gcc 7.2.1, AVX
1. Cubeful 0-ply 8/5 6/5 Eq.: +0.204
0.602 0.186 0.010 - 0.398 0.137 0.034
0-ply cubeful prune [expert]
2. Cubeful 0-ply 24/20 Eq.: +0.198 (-0.006)
0.599 0.152 0.004 - 0.401 0.128 0.027
0-ply cubeful prune [expert]
FreeBSD 11, clang 5.0.0, AVX
FreeBSD 11, gcc 7.2.0, SSE2
FreeBSD 11, gcc 7.2.0, no SIMD
CentOS 6, gcc 7.2.1, SSE2
FreeBSD 11, gcc 6.4.0, AVX
CentOS 6, gcc 6.3.1, AVX
CentOS 6, gcc 4.4.7, AVX
1. Cubeful 0-ply 8/5 6/5 Eq.: +0.102
0.551 0.174 0.013 - 0.449 0.124 0.005
0-ply cubeful prune [expert]
2. Cubeful 0-ply 24/23 13/10 Eq.: -0.006 (-0.108)
0.497 0.137 0.008 - 0.503 0.140 0.007
0-ply cubeful prune [expert]
_______________________________________________
Bug-gnubg mailing list
Bug-gnubg@gnu.org
https://lists.gnu.org/mailman/listinfo/bug-gnubg
