Search found 882 matches

by Ras
Tue Oct 18, 2016 9:00 pm
Forum: Computer Chess Club: General Topics
Topic: Why do engines lack mate solving?
Replies: 29
Views: 4736

Re: Why do engines lack mate solving?

Do you, by chance, have some example position from back then? It's long since, but just maybe?
by Ras
Tue Oct 18, 2016 8:58 pm
Forum: Computer Chess Club: General Topics
Topic: Why do engines lack mate solving?
Replies: 29
Views: 4736

Re: Why do engines lack mate solving?

Yes, these examples show the problem quite well. The mate is spotted, and with increasing depth, the mate distance decreases. The question then is when to be sure that the displayed mate is actually the sortest possible. Especially with Stockfish, the problem becomes clear. The mate is possible in 1...
by Ras
Tue Oct 18, 2016 7:35 pm
Forum: Computer Chess Club: General Topics
Topic: Why do engines lack mate solving?
Replies: 29
Views: 4736

Re: Why do engines lack mate solving?

It will always be advantageous to search first where you have better prospects of finding something. I have been thinking about this, and my solution is to just change the perspective. Instead of seeing the resulting, reduced search tree for the 7 move puzzle by Nimzowitsch e.g. as a 5-mover extend...
by Ras
Mon Oct 17, 2016 6:09 pm
Forum: Computer Chess Club: General Topics
Topic: Crafty 25.1 Release
Replies: 58
Views: 15599

Re: Crafty 25.1 Release

petero2 wrote:* Profile guided optimization is not used. (Too complicated to use when cross-compiling.)
Woah, is that actually possible, and be it for individual C files?
by Ras
Mon Oct 17, 2016 6:07 pm
Forum: Computer Chess Club: General Topics
Topic: Why do engines lack mate solving?
Replies: 29
Views: 4736

Re: Why do engines lack mate solving?

But even a full-width alpha-beta search is an extremely poor way to find mates. Well yes, I sort of have to agree. Usually, the analysis mode shows the mate earlier. For a classic 7-mover by Nimzowitsch, my analysis mode throws out the solution after 10s at depth 10 while my mate solver mode takes ...
by Ras
Sun Oct 16, 2016 11:07 pm
Forum: Computer Chess Club: General Topics
Topic: Why do engines lack mate solving?
Replies: 29
Views: 4736

Re: Why do engines lack mate solving?

They prune/reduce considerably more than that. OK, didn't know that since I'm working with a middle-class engine. I failed to get the top-class working with 192kB RAM in total. Shortest-mate finding and strongest play do not go together very well. Agree. That is why I have put in a dedicated mate s...
by Ras
Sun Oct 16, 2016 7:18 pm
Forum: Computer Chess Club: General Topics
Topic: Why do engines lack mate solving?
Replies: 29
Views: 4736

Re: Why do engines lack mate solving?

As for the ELO impact, of course I didn't imply just putting it into the usual search, but into a special mode that is just alpha-beta-minimax along with using the hash tables for positions/branches that are not mate for either side. So, avoiding any kind of pruning since this might overlook key mov...
by Ras
Sat Oct 15, 2016 10:51 pm
Forum: Computer Chess Club: General Topics
Topic: Why do engines lack mate solving?
Replies: 29
Views: 4736

Why do engines lack mate solving?

I remember the 80s when the 8 bit Mephistos were capable of dedicated mate solving, along with the interesting feature of looking for alternative solution moves. That seems to have dropped out of fashion somehow. Why? It can't be that it's hard to implement. For the CT800, it took me a weekend to ad...
by Ras
Thu Sep 29, 2016 3:30 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Help with Debugging My Chess Engine
Replies: 36
Views: 3744

Re: Help with Debugging My Chess Engine

C) I am unable to figure to reset the castle permissions in undoMove(). NG-Play is using a separate status flags stack. MakeMove() pushes the current status on the stack while UndoMove() pops it back. The castling rights are done with a flag each for the two kings and the four rooks. There is also ...
by Ras
Wed Sep 28, 2016 9:23 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Starting with move ordering.
Replies: 49
Views: 8469

Re: Starting with move ordering.

-2º: Go through all moves stored one by one without change any order, just looking at its values and at the end of all the path, load the one with high value. And swap this move to position 0 of the list. So the best move now is at position 0. The move that was at position 0 before is at the positi...