Computer Chess Club Archives


Search

Terms

Messages

Subject: Re: Robert, a little question ...

Author: Robert Hyatt

Date: 12:39:03 09/20/00

Go up one level in this thread


On September 20, 2000 at 14:36:13, Mogens Larsen wrote:

>On September 20, 2000 at 12:08:31, Robert Hyatt wrote:
>
>>On September 20, 2000 at 11:52:17, Mogens Larsen wrote:
>>
>>It is difficult.  If there is one positional best move you find near the
>>end of the search, do you give the tactical searcher a chance to search it
>>for sanity?  Suppose that fails?
>
>If the tactical searcher were to be dependent on the choice of the positionally
>best move then it should get a shot at searching the move for sanity. Would it
>be possible to, say, force the positional searcher to analyze the second best
>move from the initial search if the fail margin is big enough? This would take
>extra time of course since that move would have to be cheked tactically as well.
>
>>I am not quite sure what you mean.  In my case, I consider my search to be
>>"optimal" in the sense that it is searching the tree that I want it to search.
>>Using the current threaded approach simply searches that same tree significantly
>>faster.  I don't particularly have a requirement that all the CPUs run at the
>>same clock speed, although SMP motherboards generally do have that requirement
>>to make interrupt delivery 'sane' as well as handling a shared bus.
>
>I meant simple in the conceptual sense, ie. SMP for the sake of searching deeper
>instead of adding complexity to the evaluation. The latter might be the best
>chance of advancement in performance for computer programs. The idea of leaving
>everything to chip development seem "simple" to me, but I'm not directly
>involved so to speak.

In that case, don't assume too much.  IE I obviously use a parallel search.  And
it gives me greater depth, which I sometimes choose to trade for more knowledge
instead.  But nothing says _all_ the extra cpu horsepower is going to just go
deeper.  This is why I often say that Crafty is not doing well in blitz games,
because the assumptions I make about the hardware are wrong for fast time
controls on slower computers.  however, in allocating multiple processors to
some task like chess, it makes more sense (performance-wise) to simply tell them
all "go search that tree".  IE I would rather have a single large crew building
a house rather than several small, specialized crews.  Because one of the small
crews will often have to wait on others.  And while they are waiting, they are
not contributing...


>
>I'll mail you about the ASCII article about SMP in a not too distant future.
>
>Mogens.



This page took 0 seconds to execute

Last modified: Thu, 15 Apr 21 08:11:13 -0700

Current Computer Chess Club Forums at Talkchess. This site by Sean Mintz.