Search found 17071 matches

by bob
Wed Mar 04, 2020 5:37 pm
Forum: Computer Chess Club: General Topics
Topic: Published FEN with wrong move
Replies: 2
Views: 592

Re: Published FEN with wrong move

Not uncommon. Several authors only give the key moves for the side on move. With no intervening opponent move. Confusing to say the least. Obvious point is the h1 square for the rook.
by bob
Tue Mar 03, 2020 7:44 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Measuring Hash Collisions (once again)
Replies: 37
Views: 5539

Re: Measuring Hash Collisions (once again)

Told you to read the paper I wrote with Cozzie. :) Surprised the heck out of us as well. And you can stand even more without the program blowing up.
by bob
Tue Mar 03, 2020 7:43 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Searching fail highs shallower..
Replies: 16
Views: 2579

Re: Searching fail highs shallower..

I was really thinking about the fail-low side. There was a long discussion back in the r.g.c.c days where I thought you had mentioned the reduced-depth re-search. Didn't remember the details as I have always taken the approach to resolve the first move, period. I wanted this info so I had some idea ...
by bob
Tue Mar 03, 2020 6:05 am
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Searching fail highs shallower..
Replies: 16
Views: 2579

Re: Searching fail highs shallower..

I think it has been around a LOT longer than that. I've tried it myself (but without any improvement) but the idea for fail highs and fail lows at the root is the same. For a fail high, move ordering is broken, so starting an iteration (or two or three) shallower should speed up the search by improv...
by bob
Thu Feb 27, 2020 10:46 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Delta pruning test
Replies: 16
Views: 2278

Re: Delta pruning test

You CAN add something to your program that makes it score better than the version without. And you can also do this where it scores slightly worse against other programs, as they handle the circumstance you are working on a little better than you do. Testing against yourself is not a bad idea, but y...
by bob
Thu Feb 27, 2020 10:44 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: EPD destruction tests, part 2
Replies: 2
Views: 736

Re: EPD destruction tests, part 2

Some comments: I ran 'em all through Crafty. Rather than posting a huge file, I had Crafty print out the number of the EPD string (line number in the file, ignoring blank lines) EPD #8. I do not believe castling status should be "overridable". That's a pretty important part of a position. Crafty cal...
by bob
Thu Feb 27, 2020 12:38 am
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Zobrist key independence
Replies: 38
Views: 4798

Re: Zobrist key independence

Here's my approach: /* ************************************************************ * * * Now we search for an entry to overwrite in three * * passes. A bucket contains 4 entries in Crafty. All * * accessed by the low order bits of the current hash * * signature. * * * * Pass 1: If any signature in ...
by bob
Wed Feb 26, 2020 9:55 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: EPD destruction tests
Replies: 81
Views: 7639

Re: EPD destruction tests

1st ever computer chess tournament. I figured most any computer chess fanatic would know this.... This was a tournament where almost everything went wrong. Coko refused to play a mate in 2 (I think this was '70, could have been '71 or so). Pawns to 8th rank and staying pawns. You name it. Computer c...
by bob
Wed Feb 26, 2020 6:25 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Delta pruning test
Replies: 16
Views: 2278

Re: Delta pruning test

This is one of the keys of testing. If one copy of your program has some sort of knowledge or search feature that the other one does not, then that gets highlighted and inflates the difference between the two. Using a gauntlet of opponents makes it less likely that will happen, except for the cases ...
by bob
Wed Feb 26, 2020 6:23 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Promotions in SEE
Replies: 6
Views: 1075

Re: Promotions in SEE

Actually it is pretty safe to ignore promotions. First, all you can be capturing is a piece, which is always more valuable than the pawn. So it is not much of an issue to ignore the promotion gain. Second, if the opponent recaptures, you are down a pawn, which is still a good answer. Some try to tak...