Search found 187 matches

by Sesse
Sat Jan 25, 2020 7:05 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Why is MultiPV so slow?
Replies: 11
Views: 211

Re: Why is MultiPV so slow?

Later moves tend to be worse. Worse, means more fail-lows. More fail-lows means more time spent to resolve them. So it's not unusual to have the later moves being more costly to search and absorbing a disproportionate part of the "nodes budget". Hm. So a problem is that the engine spends a dispropo...
by Sesse
Sat Jan 25, 2020 5:59 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Why is MultiPV so slow?
Replies: 11
Views: 211

Re: Why is MultiPV so slow?

That's interesting! But shouldn't it still be sub-linear, since the later moves should be cheaper to search (better move ordering, fewer moves to search) than the main PV?
by Sesse
Sat Jan 25, 2020 5:44 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Why is MultiPV so slow?
Replies: 11
Views: 211

Re: Why is MultiPV so slow?

OK, so potentially we're either looking at something wrong in my timing, or a bona fide Stockfish bug?
by Sesse
Sat Jan 25, 2020 4:27 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Why is MultiPV so slow?
Replies: 11
Views: 211

Re: Why is MultiPV so slow?

Yes, the point of setting MultiPV to 100 is to get all moves, so it's intentional. I'm a bit confused at the importance of it being inside iterative deepening, though; I assumed iterative deepening was only run at the root?
by Sesse
Sat Jan 25, 2020 2:28 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Why is MultiPV so slow?
Replies: 11
Views: 211

Why is MultiPV so slow?

So, of course I get why MultiPV is much slower than a regular single-PV search; you can't use the cutoffs and have to research suboptimal moves to score them. But still, the slowdown seems extreme. Right now, I'm searching the same position on Stockfish 11 on very similar hardware (basically two-soc...
by Sesse
Sat Dec 14, 2019 7:14 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: An AMD compiling hunch
Replies: 12
Views: 1106

Re: An AMD compiling hunch

Are we also going to call instructions like XLAT "phony baloney" also because it perform poorly (even on Intel?) XLAT is pretty pony baloney! It's a relic of the 8086 days that wasn't really a good idea even back then. The idea that GCC doesnt have a say is wrong. The goal of the compiler should be...
by Sesse
Tue Dec 10, 2019 2:34 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: An AMD compiling hunch
Replies: 12
Views: 1106

Re: An AMD compiling hunch

It isn't really GCC's fault. Stockfish simply goes and asks the compiler (well, preprocessor) “does the CPU I'm compiling for support BMI2?”, and if so, sends BMI2 code to the compiler. GCC has no say in the matter once it has given a truthful answer. (Not that there's a good way to ask “does the CP...
by Sesse
Wed Aug 28, 2019 8:08 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Syzygy 7 piece Machine slow down
Replies: 10
Views: 2323

Re: Syzygy 7 piece Machine slow down

More RAM would help, and most likely, your SSD is also pretty slow. Failing that, you can ask to probe less often (increase SyzygyProbeDepth).
by Sesse
Thu Aug 15, 2019 3:32 pm
Forum: Computer Chess Club: General Topics
Topic: Does computer chess sponsorship exist?
Replies: 24
Views: 3729

Re: Does computer chess sponsorship exist?

jp wrote:
Wed Aug 14, 2019 11:51 pm
That may be part of the confusion. Some commentators think it's run on a "university supercomputer".
That's just because people don't know what a supercomputer is.
Is NTNU interested in chess?
Nope.
by Sesse
Wed Aug 14, 2019 7:52 pm
Forum: Computer Chess Club: General Topics
Topic: Does computer chess sponsorship exist?
Replies: 24
Views: 3729

Re: Does computer chess sponsorship exist?

I think you simply have to +ask+ the guys who matter if you have a project potentially worthy of sponsorship. Yeah, the problem is figuring out who the guys who matter is, and how to get their ear :-) And we are talking +sesse+ here, „the Norwegian super computer“ that has been mentioned again and ...