Stockfish 2.0 Available

[Hugo]

Hello Stockfish team

thank you verry much for this version.
I had one crash in a long game on my 12 core machine.
How can I switch on a logfile (not searchlog) ? So I could give helpful crash-logs.
How can I manipulate the time usage settings?
Is there any explanation about the four time-parameters?
For my taste SF 2.0 moves too quick in e.g. 60 +15, or 120 +0 games.

thanks for any hint

Clemens

[Tord Romstad]

I find that SF 2.0 has approx. 20% lower kN/s than version 1.9.

Yes, 20% slower in terms of N/s sounds about right.

Depth is the same as version 1.9 and 700 lines of code less?

How can this be?

I'm not sure I understand the question. What are you wondering about?

Tord

[Martin Thoresen]

Thanks Martin ! This is very interesting it seems Sleeping Threads OFF is slightly better going up with CPU cores.

In case your machine supports Hyper Threading could you please test with:

Code: Select all

12 CPU 64-bit | 4096 MB Hash | Sleeping Threads ON

Marco,

It sure does support Hyper Threading, but I have to go into BIOS to enable it.

Let me do that tomorrow after Division II has ended.

Best Regards,
Martin

[mcostalba]

I find that SF 2.0 has approx. 20% lower kN/s than version 1.9.

Yes, 20% slower in terms of N/s sounds about right.

In SF 2.0 we have changed the way to account for the nodes that are now updated in do_move() instead of at the beginning of search()

The reason of the change is that is easier to count the nodes searched on a given sub-tree namely below a split point. Another reason is that code is simplified by this change.

Although there is no a real change in functionality due to this different accounting scheme, user sees a different speed, but actually nothing as changed in this regard.

[CatPower]

Depth is the same as version 1.9 and 700 lines of code less?

How can this be?

I'm not sure I understand the question. What are you wondering about?

Tord

it seemed that although code was simplified the speed had dropped. as i understand from Marco's reply above this is 'cosmetic'.

[Uri Blass]

I find that SF 2.0 has approx. 20% lower kN/s than version 1.9.

Yes, 20% slower in terms of N/s sounds about right.

In SF 2.0 we have changed the way to account for the nodes that are now updated in do_move() instead of at the beginning of search()

The reason of the change is that is easier to count the nodes searched on a given sub-tree namely below a split point. Another reason is that code is simplified by this change.

Although there is no a real change in functionality due to this different accounting scheme, user sees a different speed, but actually nothing as changed in this regard.

Good to know that finally stockfish counts nodes correctly.
I think that nodes are moves that you make in the tree
If you go to the beginning of search() without making a new move then there is no new node.

[Jouni]

Also nice, that SF2 displays selective dept now! But what is "Depth: 32/9"
actually meaning? Is it totally 41 ply?

Jouni

[Tord Romstad]

Also nice, that SF2 displays selective dept now! But what is "Depth: 32/9"
actually meaning? Is it totally 41 ply?

The UCI protocol allows the engine to send two numbers, "depth" and "seldepth".

"depth" is usually used to display the iteration counter: All strong chess programs use a technique called "iterative deepening". This means that the program starts doing a very shallow search, then a slightly deeper search, and so on, until the allocated thinking time runs out. The "depth" displayed by the chess program is simply the number of such progressively deeper searches that has been performed so far.

"seldepth" has no standard meaning, and different programs use it for different purposes. In SF 2.0, it simply represents the length of the PV displayed by the program.

depth=32 and seldepth=9, as in your example, means that Stockfish is doing (or has just finished) its 32nd progressively deeper search from the root position, and that the length of the current PV is 9 plies.

[Uri Blass]

Also nice, that SF2 displays selective dept now! But what is "Depth: 32/9"
actually meaning? Is it totally 41 ply?

The UCI protocol allows the engine to send two numbers, "depth" and "seldepth".

"depth" is usually used to display the iteration counter: All strong chess programs use a technique called "iterative deepening". This means that the program starts doing a very shallow search, then a slightly deeper search, and so on, until the allocated thinking time runs out. The "depth" displayed by the chess program is simply the number of such progressively deeper searches that has been performed so far.

"seldepth" has no standard meaning, and different programs use it for different purposes. In SF 2.0, it simply represents the length of the PV displayed by the program.

depth=32 and seldepth=9, as in your example, means that Stockfish is doing (or has just finished) its 32nd progressively deeper search from the root position, and that the length of the current PV is 9 plies.

I think that the common meaning of seldepth is simply the length of the longest line that the computer searched during the search.

I think that the length of the pv does not give us new information because you can calculate it simply by looking at the pv of the program.

[Tord Romstad]

I think that the common meaning of seldepth is simply the length of the longest line that the computer searched during the search.

Yes, some programs use it for that purpose.

I think that the length of the pv does not give us new information because you can calculate it simply by looking at the pv of the program.

Only if the entire PV is visible on your monitor. Nevertheless, I personally agree: It's not a particularly interesting number, especially because the PV is built from the hash table and is often truncated anyway.