Search found 4050 matches

by syzygy
Thu Mar 19, 2020 7:46 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Strange sporadic speed limitation in engine running in Linux on Ryzen
Replies: 19
Views: 1834

Re: Strange sporadic speed limitation in engine running in Linux on Ryzen

So the slow original binary got from 2.04 mnps to 2.15 mnps after this "drop_caches" while the fast copy went from 2.15 mnps to even faster 2.17mnps (which may be inside normal error margin). My explanation for what you are seeing is that the binary is sometimes loaded into memory in a way that giv...
by syzygy
Thu Mar 19, 2020 7:09 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Turning off 50-move draw rule in Stockfish & other engines
Replies: 42
Views: 1858

Re: Turning off 50-move draw rule in Stockfish & other engines

You might give Moonfish a try. https://github.com/joergoster/Moonfish If you set "Syzygy50MoveRule" to false, this will also switch it off for the search. Thanks Joerg. Do you know when using “regular” Stockfish if you turn off the Syzygy50Moverule does the main program still enforce the 50-move-ru...
by syzygy
Tue Mar 17, 2020 11:56 am
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Turning off 50-move draw rule in Stockfish & other engines
Replies: 42
Views: 1858

Re: Turning off 50-move draw rule in Stockfish & other engines

You might give Moonfish a try. https://github.com/joergoster/Moonfish If you set "Syzygy50MoveRule" to false, this will also switch it off for the search. Thanks Joerg. Do you know when using “regular” Stockfish if you turn off the Syzygy50Moverule does the main program still enforce the 50-move-ru...
by syzygy
Thu Mar 12, 2020 8:04 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Strange sporadic speed limitation in engine running in Linux on Ryzen
Replies: 19
Views: 1834

Re: Strange sporadic speed limitation in engine running in Linux on Ryzen

It isn't a bad compilation cause if I copy the slow binary and run the copy, speed is fine. So it seems that "something in the Linux system" slows down the binary. I tried "lsof" to see if there is a process running with a handle on the slow binary but without success. Last time it happened, a rebo...
by syzygy
Tue Mar 03, 2020 10:20 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Measuring Hash Collisions (once again)
Replies: 37
Views: 3658

Re: Measuring Hash Collisions (once again)

How can that function, any idea? Well, as Bob pointed out, collisions have virtually zero impact on Elo (even when they are what you call 'transpositions', so that their score is used). Unless they are more frequent than one every 10K nodes. Which with a 16-bit signature and 3-way bucket they aren'...
by syzygy
Tue Mar 03, 2020 7:55 am
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Measuring Hash Collisions (once again)
Replies: 37
Views: 3658

Re: Measuring Hash Collisions (once again)

Now I have heard an experienced programmer say, Stockfish doing 75 million NPS will generate hundreds of collisions each second. Not my experience, ProDeo produces zero. Stockfish stores just 16 bits in a TT entry. With 3 entries per bucket, this means 1 false hit per 2^16/3=21845.33 probes that sh...
by syzygy
Wed Feb 19, 2020 1:06 am
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: hash collisions
Replies: 370
Views: 22871

Re: hash collisions

I'm going to add a couple of things that serve as responses to a few posts here. ... Good summary, except the outstanding issue (to me anyway) is which approach - pseudo legal test or handle making/unmaking illegal moves stably - is best. Not in the sense that it's "correct coding practice" or what...
by syzygy
Wed Feb 12, 2020 12:07 am
Forum: Computer Chess Club: General Topics
Topic: The most famous study cooked by computer analysis?
Replies: 16
Views: 1501

Re: The most famous study cooked by computer analysis?

Who has good candidates? Here is my candidate. 5B2/1n6/1k6/3K4/B7/8/8/8 w - - 0 1 This position was thought to be drawn for over a century. It is a mate in 57 moves! Special rule in chess. Chess rules 3: The new 75-move rule 2 states: “any series of at least 75 moves have been made by each player w...
by syzygy
Tue Feb 11, 2020 11:57 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: hash collisions
Replies: 370
Views: 22871

Re: hash collisions

I complained to the Stockfish group that badly formed EPD will cause Stockfish to crash and core dump heinously, eventually filling my disk drive with core files. Their response was: "Don't send badly formed EPD to Stockfish then." I guess we should all expect that the millions of EPD positions we ...
by syzygy
Tue Feb 11, 2020 11:52 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: hash collisions
Replies: 370
Views: 22871

Re: hash collisions

My question was, however, is 4) actually faster? Remembering pieces captured by castling, which piece promoted in case of non-pawn, searching impossible positions, etc. doesn't sound like it would be faster to me, but I might be wrong. I assume hgm has tried both, and I'd love to hear the result of...