Search found 400 matches

by Ralph Stoesser
Mon Apr 19, 2010 9:04 am
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: about hash tables and illogical behaviour of chess programs
Replies: 34
Views: 4517

Re: about hash tables and illogical behaviour of chess progr

I don't meant to get large difference in value, but in reliability of the value, depending on where refinedValue belong from, search or static evaluation. Marco, Sure. But what is your point? Below I don't bear on the razoring especially. Depth 9 is far beyond the max razor depth. Assume we are at d...
by Ralph Stoesser
Sun Apr 18, 2010 10:03 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: about hash tables and illogical behaviour of chess programs
Replies: 34
Views: 4517

Re: about hash tables and illogical behaviour of chess progr

I find that stockfish is using the following code ... I think that this behaviour is illogical. What is illogical is that you never prune when the depth is not enough and the score is not relevant. ... Actually Stockfish uses the TT score from a shallower search for null move pruning and for razori...
by Ralph Stoesser
Sun Apr 18, 2010 6:45 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: about stockfish and logic
Replies: 18
Views: 3762

Re: about stockfish and logic

Marco, Yes, I understand. I think there is nothing big to gain anyways. After 1000 10 sec self play games I can see nothing world-shuttering. Using global (per thread) variables last_eval, last_pos_key or always passing by the eval as a parameter to the child nodes may bring a tiny performance gain....
by Ralph Stoesser
Sun Apr 18, 2010 1:48 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: about stockfish and logic
Replies: 18
Views: 3762

Re: about stockfish and logic

Instead a possible optimization that I didn't make because of didn't find a nice way to do it (read "without changing qsearch() call parameters") is to pass the static position evaluation to qsearch when we razor. IOW we have already called the costly evaluate() few lines before: ss[ply].eval = eva...
by Ralph Stoesser
Sun Apr 18, 2010 9:32 am
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: about stockfish and logic
Replies: 18
Views: 3762

Re: about stockfish and logic

I also have a question regarding step 6: razoring. In case the razoring conditions are true the qsearch value v is returned. Shouldn't refinedValue be more accurate than v, in case refinedEval would come from a TT entry with depth>0? Could you please post the code you mean to change and the change ...
by Ralph Stoesser
Sat Apr 17, 2010 3:49 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: about stockfish and logic
Replies: 18
Views: 3762

Re: about stockfish and logic

I also have a question regarding step 6: razoring.
In case the razoring conditions are true the qsearch value v is returned. Shouldn't refinedValue be more accurate than v, in case refinedEval would come from a TT entry with depth>0?
by Ralph Stoesser
Tue Apr 13, 2010 6:54 pm
Forum: Computer Chess Club: General Topics
Topic: Stockfish 1.7.1 displays weird mate scores
Replies: 22
Views: 4128

Re: Stockfish 1.7.1 displays weird mate scores

bool deepChecks = (depth == -OnePly && staticValue >= beta - PawnValueMidgame / 8); is easier to read. Adding extra parentheses to the return statement would not be easier to read. Redundant parentheses are in most cases bad for clarity. The above example is an exception from this rule. All...
by Ralph Stoesser
Mon Apr 12, 2010 8:31 pm
Forum: Computer Chess Club: General Topics
Topic: Stockfish 1.7.1 update available
Replies: 52
Views: 35192

Re: Stockfish 1.7.1 update available

From 1.6 to 1.7 we have seen a new search approach. I wonder what comes next. A totally new eval? This is great piece oft software. It plays already very strong. On the other hand there seem to be much potiential for further improvements. From reading the sources and the comments within the sources,...
by Ralph Stoesser
Sun Apr 11, 2010 7:23 pm
Forum: Computer Chess Club: General Topics
Topic: Better Results with 1.7.1
Replies: 8
Views: 2642

Re: Better Results with 1.7.1

I use the zugzwang detection patch from Marco Costalba for version 1.7. Additionally I have added a condition to not try null move in case TT entry indicate it would be pointless to do so. I also think the zugzwang detection version plays rather differently. I have no game statistics but from watchi...
by Ralph Stoesser
Sat Apr 10, 2010 12:47 am
Forum: Computer Chess Club: General Topics
Topic: Stockfish-1.7.0 Hyper-threading Detection
Replies: 4
Views: 1426

Re: Stockfish-1.7.0 Hyper-threading Detection

I haven't looked at this myself Please, if interested take a look at: http://software.intel.com/en-us/articles/intel-64-architecture-processor-topology-enumeration/ If you (or someone else) is able to come up with a working patch for SF out of that document then you are my new code idol :-) At the ...