Search found 4343 matches

by syzygy
Sat Oct 31, 2020 12:21 am
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Principal Variation Search vs. Transposition Table
Replies: 17
Views: 536

Re: Principal Variation Search vs. Transposition Table

So do I understand it correctly that if you have a triangular array (or in my case, a recursive vector) for constructing the PV, you don't actually need a principal variation search because you have the PV already? No. The triangular array is hardly important as it is just a way of remembering the ...
by syzygy
Fri Oct 30, 2020 10:44 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Principal Variation Search vs. Transposition Table
Replies: 17
Views: 536

Re: Principal Variation Search vs. Transposition Table

Thanks for your insights. I know PV collection is not the same as PVS. I was just wondering if doing a PVS is still necessary if you have a transposition table. As in: you search the hash move first, then the PV move... but what if the hash move IS the PV move? Then you search a move twice. Again: ...
by syzygy
Wed Oct 28, 2020 10:37 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: NNUE Question - King Placements
Replies: 30
Views: 1258

Re: NNUE Question - King Placements

Guys, I'm a layman, but how is the Stockfish neural network trained? We know that Leela's network is trained from zero, but is NNUE training supervised? How is it done? It is trained at positions evaluated by Stockfish with shallow searches. Originally by "classical Stockfish" and now by NNUE Stock...
by syzygy
Wed Oct 28, 2020 10:30 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Principal Variation Search vs. Transposition Table
Replies: 17
Views: 536

Re: Principal Variation Search vs. Transposition Table

let's suppose that the PV contains a repetition 1) e4 Nf6 2) Nf3 Ng8 3) Ng1 Nf6 4) d4 e5 .... the Pv extracted from transposition table can be eiter 1) e4 Nf6 2) Nf3 Ng8 3) Ng1 Nf6 4) Nf3 Ng8 5) Ng1 Nf6 6) Nf3 Ng8... or 1) e4 Nf6 2) d4 e5 .... because for repeated position, only one move can be sto...
by syzygy
Mon Oct 26, 2020 2:40 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Principal Variation Search vs. Transposition Table
Replies: 17
Views: 536

Re: Principal Variation Search vs. Transposition Table

I'm thinking to collect the PV by a somewhat modernized version of the triangular array method (vectors instead of arrays, because an array would need to be 256x256 elements in my case. My MAX_PLY is 255.) So I can have a PV without finding it in a hash table. I don't think you have the PV until yo...
by syzygy
Mon Oct 26, 2020 1:27 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Principal Variation Search vs. Transposition Table
Replies: 17
Views: 536

Re: Principal Variation Search vs. Transposition Table

I may be misunderstanding this, but as I understand it now, it seems "walking the PV" (and thus, principal variation search?) For me, PVS means zero-window searches of all non-first moves. This is very useful. It is fine to use the search the TT move first. You will anyway not have the PV until aft...
by syzygy
Sun Oct 25, 2020 8:03 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Different performance of equal executables
Replies: 11
Views: 472

Re: Different performance of equal executables

Type the following as root: # echo 1 > /proc/sys/vm/drop_caches Yes, this solved it. Afterwards "bin/olithink589 performs exactly equal as "./olithink589" with 2220 knps. Now this should explain the issue: What cache went probably wrong and how can this be avoided in the future? Nothing went really...
by syzygy
Sun Oct 25, 2020 12:26 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Different performance of equal executables
Replies: 11
Views: 472

Re: Different performance of equal executables

Type the following as root:
# echo 1 > /proc/sys/vm/drop_caches

Now try again.
by syzygy
Sat Oct 24, 2020 8:44 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: NNUE Question - King Placements
Replies: 30
Views: 1258

Re: NNUE Question - King Placements

An NNUE net based on pure PST would have far fewer inputs and weights, but would not give spectacular computational savings: the only thing you save is the complete recalculation on the occasional King move. And with 9 King positions you would have to recalculate on a King move anyway. By making th...
by syzygy
Sat Oct 24, 2020 6:59 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: NNUE Question - King Placements
Replies: 30
Views: 1258

Re: NNUE Question - King Placements

If you care about worst-case behaviour then all engines suck without exception, and all humans too. Indeed, and this has always worried me. No one seems to care; they sacrifice worst-case for a better average (= Elo) all the time. I think in most areas it is more fruitful to worry about the average...