Search found 2880 matches

by Evert
Sat Aug 11, 2018 9:05 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Attacks From table
Replies: 12
Views: 1435

Re: Attacks From table

I think you can do better by testing for alignment first, and only then doing a lookup for the actual piece (your xxxAttacksBB functions) if there is alignment. You probably also want to do that in a ray-direction way, rather than by full rank/file/diagonal. You can cache the attack information for ...
by Evert
Mon Jul 30, 2018 6:16 am
Forum: Computer Chess Club: General Topics
Topic: Off topic - Who is authorized?
Replies: 6
Views: 666

Re: Off topic - Who is authorized?

You need to be logged in to view profiles now, I think.
by Evert
Thu Jun 21, 2018 11:37 am
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: about the value of fairy pieces
Replies: 10
Views: 1522

Re: about the value of fairy pieces

I think it's important to make a distinction between opening and end game values. I can imagine Crab/Barc beating a Knight in the end game simply because the Knight cannot easily defend both flanks. I also believe that the value difference between Q and B/R goes down in the end game. What would be a...
by Evert
Thu Jun 21, 2018 5:00 am
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: about the value of fairy pieces
Replies: 10
Views: 1522

Re: about the value of fairy pieces

But suppose you replace Pawns by (promoting) Ferzes (or allow FIDE Pawns to capture backwards, fmWcF). These make chains that are self-protecting, and can only be damaged at the expense of the first attacker. So it would be more helpful to have two pieces, one of which less valuable than a pair of ...
by Evert
Wed Jun 20, 2018 9:14 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: about the value of fairy pieces
Replies: 10
Views: 1522

Re: about the value of fairy pieces

Seems contrived on a normal board, normal rules and an otherwise balanced army. It would imply that B and C are due some sort of synergy bonus (generalised pair bonus) that is larger when the pieces are further apart (or at least, not on the same square). The effect HGM mentions is of course also im...
by Evert
Tue Jun 12, 2018 5:16 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: whether or not a piece has moved and how many times
Replies: 11
Views: 1667

Re: whether or not a piece has moved and how many times

Curious about how others have implemented calculation of how many times each piece has moved since the beginning of the game. The concern is when a piece has been captured in a make move and then uncaptured and updating the array. How did you solve this? I'd do it the same way I handle the 50-move ...
by Evert
Tue Jun 05, 2018 8:46 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Bitboard for a non-chess game
Replies: 4
Views: 987

Re: Bitboard for a non-chess game

You should be able to use the same logic as for pawn duo's and hanging pawns (there's a breakdown of the logic on CPW). Essentially you have to find squares that border exactly one empty square, which can be done by testing for squares that have an empty square to the West (say), but not in any of t...
by Evert
Thu May 31, 2018 12:30 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Move ordering based on stored values of child nodes
Replies: 4
Views: 790

Re: Move ordering based on stored values of child nodes

With current move ordering heuristics, you get a cut-off from the first three moves in 95-99% of cases. That's the statistic you have to beat. Any effort spent on move ordering in ALL-nodes is wasted. Any effort in improving move ordering in a CUT-node is wasted in 95-99% of cases, so whatever you p...
by Evert
Tue May 22, 2018 8:52 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: 7-men Syzygy attempt
Replies: 549
Views: 70489

Re: 7-men Syzygy attempt

Ok, so I'm sure I've asked this before, but I don't remember the explanation and I can't find it using the search. Assuming I have N-piece DTM and DTZ50 tables. Can't I get DTM50 optimal play (not value) by first reducing the move list to those moves that preserve the win (according to DTZ50), and ...
by Evert
Tue May 22, 2018 6:11 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: 7-men Syzygy attempt
Replies: 549
Views: 70489

Re: 7-men Syzygy attempt

DTM50 conceptually stores a distance-to-mate value for each pair (position, rule50_counter). So that is 100x as much raw data as for DTM. The sequence of values for a particular position is far from random, but it is not immediately obvious how to find an efficient encoding that fits into a good co...