Search found 3993 matches

by syzygy
Sat Jun 22, 2019 2:52 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Some NUMA data for Stockfish-dev and Cfish-dev
Replies: 3
Views: 455

Re: Some NUMA data for Stockfish-dev and Cfish-dev

Cfish's nps was more than 3x that of Stockfish? (Looking at "Time elapsed", maybe not.)

I suppose the difference in local/remote ratio is due to Cfish making sure that the memory for each thread is allocated on the node on which the thread runs.
by syzygy
Sat Jun 22, 2019 1:11 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: How many elo do ponder equals to
Replies: 17
Views: 445

Re: How many elo do ponder equals to

Nordlandia wrote:
Sat Jun 22, 2019 12:21 pm
Hardware is assumed to be equal.
And I suppose you will be running the engines on separate machines (or the pondering engine will compete for resources with the non-pondering engine when it is the latter's turn).
by syzygy
Fri Jun 21, 2019 12:33 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: strange code for tt
Replies: 9
Views: 539

Re: strange code for tt

Any insights? What happens when you store MOVE_NONE? Does that delete the old tt move (if there was one for the current position)? It is correct not to store the new "best" move if you haven't actually found a move that is better than start_alpha, but you should not delete the old tt move if there ...
by syzygy
Wed Jun 19, 2019 10:54 pm
Forum: Computer Chess Club: General Topics
Topic: is this an issue with missing DTZ ?
Replies: 7
Views: 340

Re: is this an issue with missing DTZ ?

Spliffjiffer wrote:
Wed Jun 19, 2019 12:58 am
i see that the bug was found and already fixed (as far as i understood)...im glad that i could help a tiny bit in terms of verifying when to search...this should close the thread, thx for the replys :-)
Thanks for reporting!
by syzygy
Tue Jun 18, 2019 11:25 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: strange code for tt
Replies: 9
Views: 539

Re: strange code for tt

Any insights? What happens when you store MOVE_NONE? Does that delete the old tt move (if there was one for the current position)? It is correct not to store the new "best" move if you haven't actually found a move that is better than start_alpha, but you should not delete the old tt move if there ...
by syzygy
Tue Jun 18, 2019 9:13 pm
Forum: Computer Chess Club: General Topics
Topic: is this an issue with missing DTZ ?
Replies: 7
Views: 340

Re: is this an issue with missing DTZ ?

syzygy wrote:
Tue Jun 18, 2019 7:45 pm
But none of the June 9 patches seem to relate to the relevant code.
I overlooked that this patch makes changes to "tbRank" in search.cpp and search.h. So that must be the problem. Should be happening in 6-piece positions too, I guess.
by syzygy
Tue Jun 18, 2019 7:45 pm
Forum: Computer Chess Club: General Topics
Topic: is this an issue with missing DTZ ?
Replies: 7
Views: 340

Re: is this an issue with missing DTZ ?

So with multiPV=5 Stockfish is showing 5 moves that lose, lose, draw, lose, lose in that order? That's pretty weird... It is correct that Kc5 draws and all other moves lose: https://syzygy-tables.info/?fen=2b5/8/3k3p/P7/8/3K1BP1/8/8_b_-_-_0_1 Of course it should not play a move that is known to lose...
by syzygy
Sun Jun 16, 2019 7:01 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: strategies for finding slowdows in lazy smp
Replies: 26
Views: 1157

Re: strategies for finding slowdows in lazy smp

Now my question is: what are strategies for finding what causes this slow down? The threads share no common variables apart from the transposition table. That tt has no locks, it uses the xor-trick. Most likely the threads share common cache lines, which has the same effect as sharing common variab...
by syzygy
Thu Jun 13, 2019 10:57 pm
Forum: Computer Chess Club: General Topics
Topic: Widely unknown pioneering chess "paper machine" by Gunter Sсhliebs
Replies: 9
Views: 588

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

G. Schlieb referred Shannon's groundbreaking paper, which is surely the base his paper. It has the same board represention (same piece codes), evaluation function and similar search ideas concerning selectivity and quiescence. And these are by far not the only similarities between the two papers. O...
by syzygy
Thu Jun 13, 2019 9:57 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: strategies for finding slowdows in lazy smp
Replies: 26
Views: 1157

Re: strategies for finding slowdows in lazy smp

Now my question is: what are strategies for finding what causes this slow down? The threads share no common variables apart from the transposition table. That tt has no locks, it uses the xor-trick. Most likely the threads share common cache lines, which has the same effect as sharing common variab...