📝Greg Strong wrote on Sat, Feb 15, 2020 03:50 PM UTC:
@HG:
I had a problem. ChessV sometimes wasn't able to find the mate in KRK (for example), despite the fact that I have a custom endgame eval for this combination (which I'm sure is correct.) I was able to solve this by no longer returning on TT hits on PV nodes. This is an acceptable solution since you seldom get a cut-off on a PV node so it does not speed things up much, if at all, and it reports shorter PVs. But I'd still like to understand the problem in case there is something else wrong.
I only return at a PV node if the TT entry depth >= depth remaining and the entry type is Exact. I also shift mate scores by the ply before returning, as is typically done. Do you have any insight why I might be missing mates and stumbling into draws by repetition or 50-moves? I guess my TT code could have a bug, but I don't think so.
@HG:
I had a problem. ChessV sometimes wasn't able to find the mate in KRK (for example), despite the fact that I have a custom endgame eval for this combination (which I'm sure is correct.) I was able to solve this by no longer returning on TT hits on PV nodes. This is an acceptable solution since you seldom get a cut-off on a PV node so it does not speed things up much, if at all, and it reports shorter PVs. But I'd still like to understand the problem in case there is something else wrong.
I only return at a PV node if the TT entry depth >= depth remaining and the entry type is Exact. I also shift mate scores by the ply before returning, as is typically done. Do you have any insight why I might be missing mates and stumbling into draws by repetition or 50-moves? I guess my TT code could have a bug, but I don't think so.