Search found 601 matches

by petero2
Sun Mar 08, 2020 9:45 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Strange sporadic speed limitation in engine running in Linux on Ryzen
Replies: 19
Views: 1833

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

I recommend to see the following video about what can affect program performance: https://www.youtube.com/watch?v=r-TLSBdHe1A Many things can affect the memory layout of the program and affect its performance, including the directory where it runs from. In particular for your situation: Does the co...
by petero2
Sun Mar 01, 2020 12:44 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)

That pretty much confirms that 16 (non-redundant) bits in the signature is already good enough from an Elo perspective. And with full verification of the hash move, Elo would be the only concern. Some of the bits in the Zobrist key are used to determine which bucket a position belongs to. Each entr...
by petero2
Sat Feb 29, 2020 12:22 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)

But the question is: "what is good enough"? I would say that 1 collision in 64M nodes is already far better than you would need to have totally undetectable impact on Elo. According to Bob 1 collison in 10K nodes should already have no measurable impact, so it seems you are several thousand times b...
by petero2
Thu Feb 27, 2020 8:21 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Don't understand CarryRippler
Replies: 14
Views: 1161

Re: Don't understand CarryRippler

Yes, i understand now. I know a number wraps around at the boundary: u8 255 + 1 = 0 u8 0 - 1 = 255 I didn't realize the carry rippler expects this, and that C implicitly allows it when using unsigned variables. Thanks for the help :) This is actually explicitly allowed by the C language specificati...
by petero2
Tue Feb 18, 2020 7:36 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: hash collisions
Replies: 370
Views: 22870

Re: hash collisions

Oh. In that case the chess equivalent might be Sting, an engine based on Stockfish 2.1.1 where all known Stockfish 2.1.1 bugs would have been fixed so any bug that it'd have would need to have survived since that version. So a bug-free version might be possible, but at what cost? (in this case, no ...
by petero2
Tue Feb 18, 2020 7:15 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: hash collisions
Replies: 370
Views: 22870

Re: hash collisions

Ovyron wrote:
Tue Feb 18, 2020 6:21 pm
Any other example of "bug-free software"
TeX version 3.14159265 might come pretty close. The latest bug fix release is 6 years old and the bounty for finding a bug is $327.68.
by petero2
Sat Feb 08, 2020 9:15 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Endgame woes
Replies: 12
Views: 1990

Re: Endgame woes

Note that you can cut off some search work in end-games that in general are draws by reducing the search depth at the point where you enter them to a value that would be enough to see any tactics that would provide a winning exit from that end-game. This is true but in practice it might be hard to ...
by petero2
Mon Jan 06, 2020 4:11 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: RMO - Randomized Move Order - yet another Lazy SMP derivate
Replies: 113
Views: 11361

Re: RMO - Randomized Move Order - yet another Lazy SMP derivate

Ok I have made history and refutation tables thread-local now but it seems there is no change at least for depth=8 will test 14 later. Score of scorpio-sht-8-thread vs scorpio-sht-1-thread: 66 - 65 - 68 [0.503] 199 My changes are very simple: make the tables local by uncommenting static, and clear ...
by petero2
Sun Jan 05, 2020 10:36 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: RMO - Randomized Move Order - yet another Lazy SMP derivate
Replies: 113
Views: 11361

Re: RMO - Randomized Move Order - yet another Lazy SMP derivate

Edit My result after the fix is not as great as Peter's but it is still there Score of stockfish-8-thread vs stockfish-1-thread: 3629 - 1130 - 1380 [0.704] 6139 +151 elo compared to +251 of Peter. Stockfish git hash I used is from Jul 14, 2019: commit 7090d2561ae9ce3803bbc04319c4c93f I tried that v...
by petero2
Sun Jan 05, 2020 8:39 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: RMO - Randomized Move Order - yet another Lazy SMP derivate
Replies: 113
Views: 11361

Re: RMO - Randomized Move Order - yet another Lazy SMP derivate

// Iterative deepening loop until requested to stop or the target depth is reached while ( (rootDepth += ONE_PLY) < DEPTH_MAX && !Threads.stop && !(Limits.depth && mainThread && rootDepth / ONE_PLY > Limits.depth)) Perhaps this is the culprit? If I read it correctly then the depth limit is only res...