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Subject: Re: next deep blue

Author: Christophe Theron

Date: 10:03:09 01/26/00

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On January 26, 2000 at 10:27:38, Robert Hyatt wrote:

>On January 26, 2000 at 01:38:07, Christophe Theron wrote:
>
>>
>>
>>I don't forget this.
>>
>>I'm just saying that the thing could have been much stronger if they had worked
>>on implementing a good pruning scheme rather than this SE thing.
>>
>>
>
>
>I definitely don't agree here.  I watched them play *socrates at an acm event,
>where *socrates was searching considerably faster than they were in terms of
>NPS, and in terms of depth of search reached.  They blew *socrates out on a
>tactical level anyway...


But you are only talking about ONE game, or maybe only a FEW games that you have
witnessed yourself.

You do not know how good or bad *Socrates pruning scheme was.

I would not conclude from this that no pruning is better than pruning.

On the other hand, years of study and practical experience have shown that using
a good pruning scheme is way better than not using one.





>>Maybe or maybe not.
>>
>>My interest was rather in the fact that they used a probably suboptimal approach
>>in a multimillion dollars project.
>>
>>Not sure anymore if you are interested in talking about this...
>>
>>
>
>
>I am always interested.  I had said before that I would like to see how I
>could play on hardware that would drive my search to a depth of 19 plies.


You seem so keen on this idea that a pruning system is not useful at deeper
levels that you should do the experiment yourself.

Let Crafty without null move play games against the normal Crafty. Give the
non-pruning one enough time to simulate a Crafty running at DB's speed.

Your null-move version will beat the non pruning one, even with a huge time
handicap.

If it doesn't, then you have a point and this would be a new and interesting
thing. You could write a paper on this, and we would better understand DB.

You have done experiments on the "dimishing returns" idea. This is related to
this idea, isn't it worth experimenting?




>But I am a long way from being ready to say "they probably used a suboptimal
>approach in a multimillion dollars project" since I don't have the hardware to
>play with.  But what if I had a null-move and non-null-move crafty, and on the
>new hardware, the non-null-move program made fewer mistakes overall?  I'd go
>with that in an instant.  Where on slower hardware the null-move depth gained
>might be very worth-while (it obviously is as I use it today)...


Do the experiment... It just requires that you let a PC run for enough time
(maybe a month or two).




>I simply can't say their way was right or wrong without testing a known program
>to see.  If all I have to go on is their results, I have to say they did well.


If you want to live on facts on this issue, you can easily do it. I'm sure you
can find a computer for this experiment.



    Christophe



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