Search found 2958 matches

by lucasart
Wed Jan 08, 2020 4:20 am
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: RMO - Randomized Move Order - yet another Lazy SMP derivate
Replies: 113
Views: 5989

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

It is only the fixed depth tests that I prefer v4, but there is no reason not to stop the search if one thread reaches the depth limit. It turns out Stockfish can be made stronger by simply repeating a single-threaded search at a given depth a number of times. In fact, it seems a single-threaded se...
by lucasart
Tue Jan 07, 2020 4:39 am
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: RMO - Randomized Move Order - yet another Lazy SMP derivate
Replies: 113
Views: 5989

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

Vondele did an interesting experiment : I implemented 5 versions (drafts: https://github.com/vondele/Stockfish/commits/threadDepth) v1: Master version: all threads search irrespective of Limits.depth, mainThread stops search when it reaches limits depth. v2: First thread to reach Limits.depth stops...
by lucasart
Sun Jan 05, 2020 11:38 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: RMO - Randomized Move Order - yet another Lazy SMP derivate
Replies: 113
Views: 5989

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

sorry, what do you mean by SHT? Shared transpositio table? SHT and Lazy are the same thing. SHT is the real name, dating back from times immemorial: https://www.chessprogramming.org/Shared_Hash_Table Lazy is just a silly name coined in this forum a few years ago, and was refering to a completely mi...
by lucasart
Sun Jan 05, 2020 10:39 am
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: RMO - Randomized Move Order - yet another Lazy SMP derivate
Replies: 113
Views: 5989

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

SF uses skip depth scheme, so the reported depth is misleading and massively understated. This is wrong. Depth skipping has been removed from Stockfish over 9 months ago, because it scales awfully at longer TCs. See https://github.com/official-stockfish/Stockfish/pull/1972 Current Stockfish doesn't...
by lucasart
Sun Jan 05, 2020 6:02 am
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: RMO - Randomized Move Order - yet another Lazy SMP derivate
Replies: 113
Views: 5989

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

It looks "ridiclous theory number 1" could be the winner :) I redid the test at fixed depth=8 but this time constraining all 8 threads to 1 cores using "taskset -c 0 ./cutechess-cli", and i can see only 100% cpu usage when the previous test was 800% cpu usage. So both the single thread and multi-th...
by lucasart
Sat Jan 04, 2020 5:52 am
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: RMO - Randomized Move Order - yet another Lazy SMP derivate
Replies: 113
Views: 5989

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

Dann Corbit wrote:
Sat Jan 04, 2020 4:04 am
Why not a hybrid?

Half of the threads are using Lazy SMP to update the hash table.
The other half of the threads are using DTS/YBW/ABDADA to update the hash table.
Or some other mix as a function of thread count, hash table size, and time.
Talk is cheap. Show us your code :lol:
by lucasart
Sat Jan 04, 2020 12:31 am
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: RMO - Randomized Move Order - yet another Lazy SMP derivate
Replies: 113
Views: 5989

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

Occam's razor says that we should first look for the simplest possible explanation. And the simplest possible explanation is that Lazy has almost zero overhead. The overhead is so small, that (combined with a few primitive tricks to avoid that threads do too much double work) it wins against (some?...
by lucasart
Fri Jan 03, 2020 11:21 am
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: RMO - Randomized Move Order - yet another Lazy SMP derivate
Replies: 113
Views: 5989

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

I did some quick tests on a ryzen 3900x with 12-physical cores (24 threads but I used only 12) at tc 40/60 ABDADA beats plain SHT by a score of 10-3-15, and YBW beats ABDADA by a score of 9-6-9 so far. Not so many games I know but It is clear to me YBW > ABDADA > SHT even at 12 threads. Lazy SMP co...
by lucasart
Fri Jan 03, 2020 11:18 am
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: RMO - Randomized Move Order - yet another Lazy SMP derivate
Replies: 113
Views: 5989

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

I did some quick tests on a ryzen 3900x with 12-physical cores (24 threads but I used only 12) at tc 40/60 ABDADA beats plain SHT by a score of 10-3-15, and YBW beats ABDADA by a score of 9-6-9 so far. Not so many games I know but It is clear to me YBW > ABDADA > SHT even at 12 threads. Lazy SMP co...
by lucasart
Fri Jan 03, 2020 11:02 am
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: RMO - Randomized Move Order - yet another Lazy SMP derivate
Replies: 113
Views: 5989

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

I found this thread http://www.talkchess.com/forum3/viewtopic.php?f=2&t=61131 where it is claimed that Lazy is worse in TTD. But it is not clear to me if the analysis is valid since some of the other threads may be searching deeper than the main thread and this would skew the reported results - I t...