Search found 178 matches

by Harald
Fri Aug 10, 2007 9:59 am
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: What are good ranges for positional values of the pieces?
Replies: 13
Views: 6636

Re: What are good ranges for positional values of the pieces

I just have no clue about this. If the positional value for the pieces (N,B,R,Q) bottom out at zero then what should their max value be in the various stages of the game--opening, middlegame, endgame--and for--conservative, balanced, aggressive--or is this a secret also. :P I have no good answer, j...
by Harald
Fri Aug 10, 2007 1:51 am
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Why material imbalance tables are needed
Replies: 17
Views: 10718

Re: Why material imbalance tables are needed

This is a reply to ideas in several postings, not only the one above. Keys made of material or piece signatures are suggested for evaluation modifiers. If you want to have a pawn signature in 48 bit you can do this: For white pawns set a bit (0 to n=23) if a pawn is on the square. x x x x x x x x g ...
by Harald
Fri Aug 03, 2007 8:38 am
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: tactical play or positional play for chess engine
Replies: 21
Views: 26217

Re: The Art of Evaluation (long)

Thanks to you, Harm Geert and Roman for your kind words! While writing long posts like the one you replied to, I sometimes wonder why I bother writing them, and fear that noone is going to do the effort of reading them. That intelligent people like you not only read what I write, but even appreciat...
by Harald
Thu Jul 19, 2007 8:25 am
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: caps->noncaps vs. goodcaps->noncaps->badcaps
Replies: 22
Views: 9882

Re: caps->noncaps vs. goodcaps->noncaps->badcaps

Bob, Yes, you are correct. What I was talking about is a typical mistake in coding MVV/LVA. The proper way will put QxQ before PxR and RxR before PxB. So, complete ordering is: PxQ, B|NxQ, RxQ, QxQ, PxR, QxR, B|NxR, RxR, PxB|N, B|NxB|N,RxB|N, QxB|N, ........ However, the typical coding mistake (but...
by Harald
Thu Jul 19, 2007 8:11 am
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Where to put timeout() code in search?
Replies: 14
Views: 7258

Re: Where to put timeout() code in search?

Instead of returning up the chain you could use setjmp/longjmp, if you are able to clean up any temporary data structures used by search (repetition hash table or w/e). I throw an exception to return to the main loop, but I don't know if this is slower than the normal abort check in the search and ...
by Harald
Wed Jul 11, 2007 8:13 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: From PGN databases to a better evaluation
Replies: 4
Views: 2791

From PGN databases to a better evaluation

Use a PGN database to improve the evaluation. Larry Kaufman did it, Rybka does it, Strelka does it and I nearly did it. No, not really. I never found the time to even begin with it, but I had some ideas that I released in a chat and a forum. Vasik's reaction was: "It will not work that way." And tha...
by Harald
Wed Jun 20, 2007 8:44 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Passed Pawns Up
Replies: 6
Views: 4035

Re: Passed Pawns Up

http://www.top-5000.nl/authors/rebel/chess840.htm Comments are welcome. Ed I like the Rebel description very much. I could not see the pawn information in my browser Firefox. When I tried MS Internet Explorer a lot of hidden things appear and the internal links suddenly work. - Please make the text...
by Harald
Mon Apr 09, 2007 6:06 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Open Source bitbase program
Replies: 21
Views: 36320

Re: Open Source bitbase program

The first time I read about bitbases was like this: http://supertech.lcs.mit.edu/~heinz/ps/know_edb.ps.gz : Preprint of an article in: ICCA Journal 22(2), pp. 81-97, June 1999. Knowledgeable Encoding and Querying of Endgame Databases Ernst A. Heinz Institute for Program Structures and Data Organizat...