Search found 16792 matches

by bob
Sun Aug 11, 2019 2:21 am
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: SYZYGY question
Replies: 7
Views: 1534

SYZYGY question

Ronald: I have been looking at a quirk for a good while the last couple of days. First, here is the troubling position: [D]8/8/8/kPK5/p7/8/1P6/8 w - - I am seeing two oddities. If I type "go" here, I see the instant results of "b4+ null". The null is the quirk. If I do other positions without EP pos...
by bob
Sat Aug 10, 2019 2:08 am
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: draw masking a win
Replies: 8
Views: 1245

Re: draw masking a win

As a note, there are other drawing lines. Takes Crafty about 4 secs on my MacBook to discover that the capture on g3 is better than a draw... Here's my output: 26 2.54 0.00 1. ... Nxg3 2. Nxg3 Qxf3 3. Nxe2 Bh3 4. Nf4 Qg4+ 5. Kh1 Qxf4 6. c4 Bg4 7. Kg2 Be2 8. Rxa6 Bxc4 9. Ra8+ Kg7 10. Qc3+ f6 11. f3 Q...
by bob
Sat Aug 10, 2019 2:03 am
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: New crafty version
Replies: 9
Views: 1621

New crafty version

I just fixed a bug found by a crafty user. Basic idea was that after the syzygy implementation, I left a piece of code in iterate.c that could cause a nasty issue (playing a null move at the root and blowing up). Minor fix to solve this. If anyone is interested in distributing this, let me know and ...
by bob
Thu Aug 08, 2019 4:04 am
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: killer index by "ply" or "ply"
Replies: 16
Views: 3332

Re: killer index by "ply" or "ply"

maybe I misread. IE after Nb5 the opponent gets to move, and at that ply the killers for ply+1 would be zeroed? Which mean Nc7 would not be found as a killer...

Did I misunderstand?
by bob
Wed Aug 07, 2019 3:12 am
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: killer index by "ply" or "ply"
Replies: 16
Views: 3332

Re: killer index by "ply" or "ply"

No, the killer in the first example is Nxc7, or even Nc7 if there is no pawn there. In the second example, Nb5 is the killer that enables Nc7 to win the exchange. Killers might be a specific escape from check, or a specific piece move to escape some threat, etc. My main point was that at ply N, tryi...
by bob
Tue Aug 06, 2019 4:38 am
Forum: Computer Chess Club: General Topics
Topic: how much time does your engine need to see the draws?
Replies: 4
Views: 1065

Re: how much time does your engine need to see the draws?

six seconds on my MacBook for the first. (using 5 piece Ronald's EGTB data (WDL)

second one unknown. Quit after 1 minute. Much harder since pawn captures are likely, creating queens pretty quickly in many variations.
by bob
Tue Aug 06, 2019 4:34 am
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: killer index by "ply" or "ply"
Replies: 16
Views: 3332

Re: killer index by "ply" or "ply"

I remember when Dave Slate wrote the first paper I saw on this topic. He gave a position where black was on move, and white had the move Nxc7+ forking the black king and rook. As black tries different moves, almost ALL are refuted by the same move, Nxc7. Except for say Rac8 and Kd8 or Kd7 or even Kf...
by bob
Wed Jul 17, 2019 3:02 am
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Need help to make Crafty work
Replies: 31
Views: 3997

Re: Need help to make Crafty work

cores=1 is illegal so far as Crafty is concerned. cores=0 says to disable the SMP thread stuff completely. If it accepted cores=1 it would incur some overhead that gains nothing useful at all. Has always been that way. The ideal solution would probably be to parse the cores command and if it is <= 1...
by bob
Fri Jul 12, 2019 3:40 am
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Need help to make Crafty work
Replies: 31
Views: 3997

Re: Need help to make Crafty work

Yes, this was on my mac. But the way Crafty handles input is quite serial. IE a chunk of text is read, and everything up to the first new line character (or ; if I remember correctly) is executed. Then the next segment of the input, again up to the new line or ; is read and executed. I don't see any...
by bob
Thu Jul 11, 2019 3:19 am
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Need help to make Crafty work
Replies: 31
Views: 3997

Re: Need help to make Crafty work

For the record, after I type "go" and wait a couple of seconds and type "force" crafty stops the search instantly. It will probably announce a move, but since you put it into force mode, you probably have something else in mind anyway. Winboard protocol is quite simple. Which means it has a few ambi...