Stockfish 4

[mcostalba]

Stockfish 4 has been released. You can download at http://stockfishchess.org/ or browse the sources at https://github.com/mcostalba/Stockfish

Diffs from last version is: 43 files changed, 1534 insertions(+), 1703 deletions(-)

So 169 lines of code less but should be quite stronger than version 3. For interested people here is the breakdown of lines count.

Code: Select all

-------------------------------------------------------------------------------
Language                     files          blank        comment           code
-------------------------------------------------------------------------------
C++                             20           2110           1619           5772
C/C++ Header                    21            636            570           1558
-------------------------------------------------------------------------------
SUM:                            41           2746           2189           7330
-------------------------------------------------------------------------------

This is the first release where we have took full advantage of the power of our distributed and public testing framework. At one point we reached 41 active machines connected for a total of 136 cores and a compound testing power of 190M nps (nodes per second). This is even more noteworthy considering that Gary’s 24 core monster was offline at that moment.

But is the the ‘public’ part of our development model that is the real advantage we have and without which the improvement above SF 3 would have not been possible, no matter how hardware we throw at it.

So here is the list of developers that contributed to this release:

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Dan Schmidt
Dariusz Orzechowski
Eelco de Groot
Gary Linscott
jhellis3
Joona Kiiski
jundery
Leonid Pechenik
Marco Costalba
Reuven Peleg
Ryan Schmitt
Ryan Takker
Tom Vijlbrief
Uri Blass

A special thank to Daylen Yang, our precious webmaster and builder of the Mac binaries, to Peter Österlund for the Android version and to http://abrok.eu/stockfish/ from which I have, shameless, took the Windows binaries.

For the first time since Stockfish was borne, Jim Ablett didn’t compile the official builds and this is a big miss for us and for me in particular. I’d like to publicly thank him again for the help and support during all these years.

Finally a note for the user. In this version there is no more automatic detection of CPU count, so at startup Stockfish always defaults to 1 thread. In case you want to use more than one CPU you have to manually set the “Threads” UCI option accordingly.

Have Fun
SF Team

[Graham Banks]

Stockfish 4 has been released. You can download at http://stockfishchess.org/ or browse the sources at https://github.com/mcostalba/Stockfish

Thanks to all who contributed.

[JuLieN]

Goodie! Thanks Marco & al.!

[Lyudmil Tsvetkov]

Thanks Marco!

And thanks all the big team.

And remember: the winner takes it all.

[fern]

My goodness, around 30 ply in middle game!!!

What a degree of pruning!!!

Fern

[mcostalba]

My goodness, around 30 ply in middle game!!!

What a degree of pruning!!!

Fern

Never suspected you like to indulge on these pretty dry technical details

Anyhow, just to add another technical detail, that I forgot to mention in the announcement, for the people compiling themselves please verify build is ok running:

./stockfish bench

Searched node count must be: 4132374

[reflectionofpower]

thanks for heads up

[Joerg Oster]

Thanks! Great achievement.
And good luck for the nTCEC Season 2.

Jörg

P.S. Damn, I didn't make it on this list. Maybe next time.

[JuLieN]

Finally a note for the user. In this version there is no more automatic detection of CPU count, so at startup Stockfish always defaults to 1 thread. In case you want to use more than one CPU you have to manually set the “Threads” UCI option accordingly.

Have Fun
SF Team

It doesn't work with HIARCS Chess Explorer on Mac. Even when setting the number of threads to 8 it keeps running with one thread. I just tried with ScidVsMac and there it works. So it's a HCE bug, not a problem from Stockfish... for Windows' HCE users : do you have the same problem ?

[Henk]

My goodness, around 30 ply in middle game!!!

What a degree of pruning!!!

Fern

Getting a PV of 30 ply is easy. If move is PV then search (depth -1) else search(depth -5).

So in real (like in the old days) they search 30/5 is 6 ply.