Search found 1628 matches

by Gerd Isenberg
Thu Oct 10, 2019 9:38 am
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Understanding first rank attack state generation
Replies: 15
Views: 2756

Re: Understanding first rank attack state generation

Because of the inner six bit mask with 01111110b, which would usually require an additional shift right 1 for a 0..63 range, is already implicitly multiplied by two (0,2,4,....126). With a two-dimensional array it takes one additional instruction ;-) BYTE arrFirstRankAttacks64x8[64][8]; // 512 Bytes...
by Gerd Isenberg
Thu Oct 10, 2019 5:52 am
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Understanding first rank attack state generation
Replies: 15
Views: 2756

Re: Understanding first rank attack state generation

BYTE arrFirstRankAttacks64x8[64*8]; // 512 Bytes = 1/2KByte U64 rankAttacks(U64 occ, enumSquare sq) { unsigned int file = sq & 7; unsigned int rkx8 = sq & 56; // rank * 8 occ = (occ >> rkx8) & 2*63; U64 attacks = arrFirstRankAttacks64x8[4*occ + file]; return attacks << rkx8; } What I am still not c...
by Gerd Isenberg
Tue Jul 09, 2019 7:34 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: LMP
Replies: 8
Views: 1581

Re: LMP

Hi, What is LMP and how does it work/is it implemented? LMP, late move pruning not reduction. I see mentions of it here and there but it is not described on the wiki. Mentioned on the Futility Pruning page as Move Count Based Pruning aka Late Move Pruning (LMP) with reference post by Tom King.
by Gerd Isenberg
Sun Jul 07, 2019 7:16 am
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: backward pawn
Replies: 5
Views: 1265

Re: backward pawn

You are right. The routine should exclude rams: U64 wBackward(U64 wpawns, U64 bpawns) { U64 stops = (wpawns << 8) & ~bpawns; U64 wAttackSpans = wEastAttackFrontSpans(wpawns) | wWestAttackFrontSpans(wpawns); U64 bAttacks = bPawnEastAttacks(bpawns) | bPawnWestAttacks(bpawns); return (stops & bAttacks...
by Gerd Isenberg
Sat Jul 06, 2019 8:26 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: backward pawn
Replies: 5
Views: 1265

Re: backward pawn

You strictly are right. The routine may exclude rams (or even stops not occupied by any pawn): U64 wBackward(U64 wpawns, U64 bpawns) { U64 stops = (wpawns << 8) & ~bpawns; U64 wAttackSpans = wEastAttackFrontSpans(wpawns) | wWestAttackFrontSpans(wpawns); U64 bAttacks = bPawnEastAttacks(bpawns) | bPaw...
by Gerd Isenberg
Sun Jun 30, 2019 8:20 pm
Forum: Computer Chess Club: General Topics
Topic: Cock de Gorter passed away
Replies: 20
Views: 4769

Re: Cock de Gorter passed away

My condolences to his wife and family as well. RIP Cock de Gorter and thank you for organizing the Aegon tournaments.

Gerd Isenberg
by Gerd Isenberg
Thu Jun 13, 2019 3:27 pm
Forum: Computer Chess Club: General Topics
Topic: Widely unknown pioneering chess "paper machine" by Gunter Sсhliebs
Replies: 9
Views: 1668

Re: Widely unknown pioneering chess "paper machine" by Gunter Sсhliebs

I never seen [4] (but started some attempts to obtain the scan of this article) <...> 4. Sсhliebs G. (1953). Über die Gründzuge eines Programms für eine Schachspielende Rechenmaschine / Funk und Ton, 1953, vol. 7, pp. 257—265. Hooray!! Here is the paper: https://yadi.sk/d/my7VqYaYaaLc1w And it look...
by Gerd Isenberg
Wed Jun 12, 2019 12:20 pm
Forum: Computer Chess Club: General Topics
Topic: Widely unknown pioneering chess "paper machine" by Gunter Sсhliebs
Replies: 9
Views: 1668

Re: Widely unknown pioneering chess "paper machine" by Gunter Sсhliebs

In order not to create a separate topic for the sake of one message, I will write here. There is an interesting article by David Levy "Alan Turing on Computer Chess" from S. Barry Cooper, J. van Leeuwen "Alan Turing: His Work and Impact" about Turing's "paper machine": googlebooks Thanks! I missed ...
by Gerd Isenberg
Sun Jun 09, 2019 5:37 pm
Forum: Computer Chess Club: General Topics
Topic: The mystery of Alex Bernstein
Replies: 25
Views: 3533

Re: The mystery of Alex Bernstein

The most intriguing part from my point of view is "his flagging interest in mathematics revived by a kind woman who had known his father, a well-known European mathematician". Who was his father?.. Benjamin Abram Bernstein [https://en.wikipedia.org/wiki/Benjamin_Abram_Bernstein]? Felix Bernstein [h...
by Gerd Isenberg
Sun Jun 09, 2019 7:54 am
Forum: Computer Chess Club: General Topics
Topic: The mystery of Alex Bernstein
Replies: 25
Views: 3533

Re: The mystery of Alex Bernstein

Finally I've got some progress! :) McCorduck, P. (2004). Machines who think: a personal inquiry into the history and prospects of artificial intelligence (2. Edition). London: A.K. Peters. // https://books.google.ru/books?id=aH9QAAAAMAAJ Great finding! Pamela McCorduck was married to Joseph F. Trau...