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Subject: Re: Searching 18-20 ply just using nullmove

Author: Vincent Diepeveen

Date: 04:20:20 08/18/00

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On August 18, 2000 at 02:11:40, Dann Corbit wrote:

>On August 17, 2000 at 23:43:57, Vincent Diepeveen wrote:
>[snip]
>>>Assuming a doubling of CPU power every year, how long until Diep can achieve 18
>>>plies on average at 40/2?
>>
>>Oh well in wcc 99 at 3 minutes a move at a quad xeon from Bob,
>>with 400mb hash in endgame i searched always 15 to 20 ply.
>>
>>However endgame of DIEP was real BAD then. Now after i improved endgame
>>considerable, it suddenly searches a lot less there! i haven't figured
>>out yet why it doesn't search that deep in endgame anymore.
>>
>>My focus obviously is not at depth, but at evaluation!
>>That is, first get a few plies, then fix evaluation!
>>
>>At 5:43 AM here it's hard to calculate, taking into account bigger
>>hashtables as i have now!
>>
>>First let's do a few experiments next few weeks with this 256mb RAM dual 800,
>>then after that let's extrapolate it!
>
>We can do the same calculation for Crafty fairly easily.
>
>The CAP database has an average of 13 plies at 12 minutes of CPU time.  It is
>predominated by opening positions, but we'll call it good enough as an average.
>
>That is 12 minutes of PII 300 MHz to reach that depth.  If we assume an average
>branching factor of 3, that would give 36 minutes to 14 ply, 108 minutes to 15
>ply, 324 minutes to 16 ply, 972 minutes to 17 ply and 2916 minutes to 18 ply.
>
>Now, this is only a PII 300.  If we up that to 900 MHz machine we are back to
>972 minutes.  Obviously, you could do a lot better on an 8 CPU machine or
>something exotic like that, but we will stick to "state of the art and yet not
>out of reach" machines of today.
>
>40 moves in 2 hours averages 3 minutes per move.
>972/3 = 324 times faster.
>That would mean in 9 years, by hardware advances alone, Crafty should make about
>18 plies on average at tournament time controls on a single CPU, fairly
>state-of-the-art machine.
>
>On the other hand, it seems that a 64 CPU Alpha might be right about that
>neighborhood in power (give or take a factor of 2).  So if you have a fat
>wallet, maybe nine years from now is tomorrow.

First of all a 64 cpu machine is like, let's guess: 50 million dollars?

So also in 9 years of time we can't afford that.

Secondly a 64 processor alpha is perhaps not having shared memory, so getting
a good speedup is real tough then.

But i think bigger hashtables are giving your goal quicker as you think.






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