Stockfish 1.7

[Christian Goralski]

Hi,

same problem here!

Deep Fritz 12 GUI
i7 950 Windows 7 x64 ultimate


Sincerely Christian Goralski

[snino64]

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).
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[Werner]

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

[Aaron Becker]

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]

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.

[michiguel]

I'd agree with you. It detected 2 threads on my quad, fortunately I saw that before I started testing it on playchess . 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]

I'd agree with you. It detected 2 threads on my quad, fortunately I saw that before I started testing it on playchess . 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

[Eelco de Groot]

I'd agree with you. It detected 2 threads on my quad, fortunately I saw that before I started testing it on playchess . 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

[Eelco de Groot]

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

[bigo]

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