Search found 5 matches

by Rein Halbersma
Fri Dec 28, 2012 10:13 am
Forum: Programming and Technical Discussions
Topic: accelerated PVS
Replies: 7
Views: 4671

Re: accelerated PVS

yes I had noticed the typo but I thought it was in the pseudo-code only, not in your real code!
by Rein Halbersma
Thu Dec 27, 2012 2:13 pm
Forum: Programming and Technical Discussions
Topic: accelerated PVS
Replies: 7
Views: 4671

Re: accelerated PVS

What would be interesting is to collect a whole bunch of statistics in the following way. Make a class CollectStats with an array[depth][move number][search type] of chars, and then for every PV node's moves 2...N run up to 3 out of all 4 types of searches:
(1) null-window && reduced-depth
(2) null ...
by Rein Halbersma
Wed Dec 26, 2012 11:18 pm
Forum: Programming and Technical Discussions
Topic: accelerated PVS
Replies: 7
Views: 4671

Re: accelerated PVS

Your analysis reminds me of the difference between PVS with aspiration windows at the root (let's abbreviate this as asp-PVS) and MTD(f). There's an old post on CCC where Fabien Letouzey explains this much better than I could, but here's my own summary.

Both algorithms start a new iteration with a ...
by Rein Halbersma
Fri Apr 01, 2011 8:27 am
Forum: Programming and Technical Discussions
Topic: Strange Stockfish behavior?
Replies: 145
Views: 48218

Re: Strange Stockfish behavior?


Then perhaps "static eval" is not a good way to prune/reduce moves in the first place?

And nobody is suggesting that you "blindly play move X". If, at the start of depth N, move A is best, then B fails high and fails low on the re-search, B is the move to play. Unless C, D, ... fail high in which ...
by Rein Halbersma
Thu Mar 31, 2011 10:21 am
Forum: Programming and Technical Discussions
Topic: Strange Stockfish behavior?
Replies: 145
Views: 48218

Re: Strange Stockfish behavior?

There are two possible cases here.

If you get a fail high first, and then a fail low, I would trust the fail high. It is almost always caused by a TT entry that is a bound, left over from a deeper search. You get the fail high, come back with the research with a higher beta value, and now that TT ...