Stockfish 1.7

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Christian Goralski
Posts: 26
Joined: Sat Jan 09, 2010 12:06 pm

Re: Stockfish 1.7

Post by Christian Goralski » Thu Apr 08, 2010 9:24 pm

Hi,

same problem here!

Deep Fritz 12 GUI
i7 950 Windows 7 x64 ultimate


Sincerely Christian Goralski

snino64
Posts: 35
Joined: Mon Oct 05, 2009 12:38 pm

Re: Stockfish 1.7

Post by snino64 » Thu Apr 08, 2010 9:27 pm

I have a i7 920. and I get Threads (4) [4], but and I can choose eight and I work all. If I choose proportionately less work (8 threads - 100%, 6 threads - 75%, 4 threads - 50% processor usage).
[/img]

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Werner
Posts: 2428
Joined: Wed Mar 08, 2006 9:09 pm

Re: Stockfish 1.7

Post by Werner » Thu Apr 08, 2010 9:31 pm

mcostalba wrote:Could you (and also all the other people that experience problems with CPU detection) please post type of CPU you have ? Thanks.
detects 2 CPUs on QX6700 and I7 920
Werner

Aaron Becker
Posts: 292
Joined: Tue Jul 07, 2009 2:56 am

Re: Stockfish 1.7

Post by Aaron Becker » Thu Apr 08, 2010 9:56 pm

Dann Corbit wrote:
Aaron Becker wrote:
nepossiver wrote:Was Dann Corbit smooth scaling introduced into the source? I remember the few tests done showed either no difference or a 20-30 increase in ELO (which is what I found in 1+1 games).
Here is the new nullmove depth reduction calculation:

Code: Select all

        // Null move dynamic reduction based on depth
        int R = 3 + (depth >= 5 * OnePly ? depth / 8 : 0);

        // Null move dynamic reduction based on value
        if (refinedValue - beta > PawnValueMidgame)
            R++;
I don't know how close this is to Dann's formulation.
it's a new and very interesting idea (I never saw it before) that will prune more and more aggressively as a function of existing search depth.

For instance, if you are at a depth of 32, R would be 3+4=7.
Did you ever see a 7 ply reduction before? It's the most unheard of thing I have ever heard of!
;-)
It's actually pretty similar to the way I do it in Daydreamer (at depth 32 I would reduce by 10.5-12 depending on the current evaluation and search bounds, which is probably a bit crazy):

Code: Select all

        float null_r = 2.0 + ((depth + 2.0)/4.0) +
            CLAMP(0, 1.5, (lazy_score-beta)/100.0);

zullil
Posts: 5684
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Location: PA USA
Full name: Louis Zulli

Re: Stockfish 1.7

Post by zullil » Thu Apr 08, 2010 10:53 pm

Hi Marco,

I inserted

Code: Select all

printf("%d   %d    %d\n", nLogicalCPU, nCores, builtin_cpu_count());
and received 16 8 8.

Thus

Code: Select all

int cpu_count() {

  return HT_enabled() ? builtin_cpu_count() / 2 : builtin_cpu_count();
will return 8 / 2 = 4.

(I cannot find a method to disable hyper-threading under OS X 10.6.3. The Apple supplied Preference Pane simply does not work.)

In any case, nCores has the correct number of physical cores. I have two Intel 5520 quad core processors.

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michiguel
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Re: Stockfish 1.7

Post by michiguel » Thu Apr 08, 2010 10:57 pm

mcostalba wrote:
alpha123 wrote: I'd agree with you. It detected 2 threads on my quad, fortunately I saw that before I started testing it on playchess :wink:. It does use all 4 when set too, though.

Guys, maybe a 1.7.1 with proper thread detection and null move bug fix is needed.

Peter
Could you (and also all the other people that experience problems with CPU detection) please post type of CPU you have ? Thanks.

The null move bug will require regression test anyway so although the fix could be quick the testing will take some time and we would wait at least a week or two to collect all the bug reports before to release a mainteinance version.
What is the philosophical idea behind auto detecting then number of cores? Based on the things I read before, in the spirit of SF it looked like it should leave this task to the interface. Right?

Miguel

alpha123
Posts: 660
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Location: Colorado, USA

Re: Stockfish 1.7

Post by alpha123 » Thu Apr 08, 2010 10:59 pm

mcostalba wrote:
alpha123 wrote: I'd agree with you. It detected 2 threads on my quad, fortunately I saw that before I started testing it on playchess :wink:. It does use all 4 when set too, though.

Guys, maybe a 1.7.1 with proper thread detection and null move bug fix is needed.

Peter
Could you (and also all the other people that experience problems with CPU detection) please post type of CPU you have ? Thanks.

The null move bug will require regression test anyway so although the fix could be quick the testing will take some time and we would wait at least a week or two to collect all the bug reports before to release a mainteinance version.
Intel Core 2 Quad Q8300 @ 2.50gHz, 6GB DDR2, Windows 7 Home Premium 64-bit.

Peter

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Eelco de Groot
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Location: Groningen

Re: Stockfish 1.7

Post by Eelco de Groot » Thu Apr 08, 2010 11:36 pm

michiguel wrote:
mcostalba wrote:
alpha123 wrote: I'd agree with you. It detected 2 threads on my quad, fortunately I saw that before I started testing it on playchess :wink:. It does use all 4 when set too, though.

Guys, maybe a 1.7.1 with proper thread detection and null move bug fix is needed.

Peter
Could you (and also all the other people that experience problems with CPU detection) please post type of CPU you have ? Thanks.

The null move bug will require regression test anyway so although the fix could be quick the testing will take some time and we would wait at least a week or two to collect all the bug reports before to release a mainteinance version.
What is the philosophical idea behind auto detecting then number of cores? Based on the things I read before, in the spirit of SF it looked like it should leave this task to the interface. Right?

Miguel
I think the idea is that you can set the number of threads to use by the program as an UCI option, but the program then still has to see if there are enough cores available or else it will severely underperform.

Hyperthreading is a complication. You could leave the whole task to the GUI I suppose but I don't know of any GUI that can actually do this so it is a bit academic...

At least that is what I got but have not really followed the discussions as I'm only on a single core.

Eelco
Debugging is twice as hard as writing the code in the first
place. Therefore, if you write the code as cleverly as possible, you
are, by definition, not smart enough to debug it.
-- Brian W. Kernighan

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Eelco de Groot
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Location: Groningen

Re: Stockfish 1.7

Post by Eelco de Groot » Fri Apr 09, 2010 12:17 am

Dann Corbit wrote:
Aaron Becker wrote:
nepossiver wrote:Was Dann Corbit smooth scaling introduced into the source? I remember the few tests done showed either no difference or a 20-30 increase in ELO (which is what I found in 1+1 games).
Here is the new nullmove depth reduction calculation:

Code: Select all

        // Null move dynamic reduction based on depth
        int R = 3 + (depth >= 5 * OnePly ? depth / 8 : 0);

        // Null move dynamic reduction based on value
        if (refinedValue - beta > PawnValueMidgame)
            R++;
I don't know how close this is to Dann's formulation.
it's a new and very interesting idea (I never saw it before) that will prune more and more aggressively as a function of existing search depth.

For instance, if you are at a depth of 32, R would be 3+4=7.
Did you ever see a 7 ply reduction before? It's the most unheard of thing I have ever heard of!
;-)
Am I hearing some criticism here? This too simple Dann :) ? You want to do a reduction of seven plies only for very promising moves and the rest should be reduced by cos²ln√π(α + Δ(approximateEval - β) + depth) + log(number of days between Easter 2010 and the start of the new Mayan calendar)?

I'm sure we can arrange that!

We can nullmove, faster, deeper, better than anybody in the business regards,

Eelco
Debugging is twice as hard as writing the code in the first
place. Therefore, if you write the code as cleverly as possible, you
are, by definition, not smart enough to debug it.
-- Brian W. Kernighan

bigo

Re: Stockfish 1.7

Post by bigo » Fri Apr 09, 2010 12:25 am

why bother to realease something if it's not stronger?? do you enjoy wasting everyones time???
:evil:

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