Search found 3002 matches

by lucasart
Sun Feb 23, 2020 2:12 am
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: EPD destruction tests
Replies: 81
Views: 7302

Re: EPD destruction tests

And more cases of broken castlings positions, not covered by the list from Chris, which Demolito still fails to detect: krr5/8/8/8/8/8/8/4K3 w kq - 0 1; two castling rooks on same side of black king krr5/8/8/8/8/8/8/4K3 w bc - 0 1; same as above Shredder-FEN version r3k2r/8/8/8/8/8/8/4K3 w bg - 0 1...
by lucasart
Sat Feb 22, 2020 8:45 am
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: EPD destruction tests
Replies: 81
Views: 7302

Re: EPD destruction tests

First two are NOT correct. White or black can never have more that 16 pieces counting king. Not 17 or 18. The rules of chess say 16 pieces. 8 pawns, two rooks, bishops and knights, queen and king. The pawns can promote into 8 pieces excluding kings So 16 is it unless you are doing non-chess. For th...
by lucasart
Sat Feb 22, 2020 4:48 am
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: EPD destruction tests
Replies: 81
Views: 7302

Re: EPD destruction tests

First two are NOT correct. White or black can never have more that 16 pieces counting king. Not 17 or 18. The rules of chess say 16 pieces. 8 pawns, two rooks, bishops and knights, queen and king. The pawns can promote into 8 pieces excluding kings So 16 is it unless you are doing non-chess. For th...
by lucasart
Sat Feb 22, 2020 1:23 am
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: EPD destruction tests
Replies: 81
Views: 7302

Re: EPD destruction tests

Some of these are fine, and some are broken. What should engines do? What do engines do? Disclaimer/admission: my C code fails because of not much integrity testing at all, but is on the todo list. While my test engine doesn't return in any sensible time in the case of 30 queens. Meanwhile, in Pyth...
by lucasart
Thu Feb 20, 2020 5:42 am
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: EPD destruction tests
Replies: 81
Views: 7302

Re: EPD destruction tests

It depends on what positions the engine can (or is willing) to handle. If it has no problem playing with 15 Queens, it would be a waste to prevent the user from exercising that capability. If its piece-list structure (say) would only allow for 3 Queens max, you will be forced to refuse the position...
by lucasart
Mon Feb 17, 2020 4:41 am
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: hash collisions
Replies: 370
Views: 34094

Re: hash collisions

You don't like it when your stupidity receives extra attention? Hahahaha! 100% no bugs for chess engines is entirely possible, the mechanics of moving the six pieces in defined ways over 64 squares and performing recursive search are quite trivial. Programmers who won’t work to 100% bug free method...
by lucasart
Sun Feb 16, 2020 2:18 am
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: hash collisions
Replies: 370
Views: 34094

Re: hash collisions

Chess programs are pretty large. Chess programs are trivial. Their beauty lies is in the algorithms they use. I've just looked and Crafty is 24.7k sloc (including 3rd party tablebase code of course), StockFish is 6.2k, Demolito is only 2.2k... Cheng is 14.6k because I did a bad job, I admit. Still ...
by lucasart
Tue Feb 04, 2020 12:19 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: hash collisions
Replies: 370
Views: 34094

Re: hash collisions

There are two different things: 1. The possibility that distinct positions produce the same hash. 2. The possibility that two threads compete, one writing the hash entry while another is reading the same entry. The lockless hash method prevents 2. I don't think it prevents 1 or resolves the possibl...
by lucasart
Tue Feb 04, 2020 12:09 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: hash collisions
Replies: 370
Views: 34094

Re: hash collisions

I recently got a note from TCEC team and they were basically saying that since they are going to be running on 176 cores for the next season, they are concerned that engines be able to handle this well. They mention this testing technique suggested by the Demmolito author: I found a crashing bug li...
by lucasart
Sun Feb 02, 2020 7:57 am
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Stockfish Reverts 5 Recent Patches
Replies: 9
Views: 2779

Re: Stockfish Reverts 5 Recent Patches

The reverted patches passed as "elo gainers". Are we sure this pentanomial test is correct ? When I look at these [0-2] results, I'm very surprised by how low the stopping time is, compared to what you'd expected it to be for SPRT(0,2). And considering that SPRT is asymptotically optimal, something...