Computer Chess Club Archives




Subject: Re: Parallel algorithms in chess programming

Author: Vincent Diepeveen

Date: 02:25:52 04/18/01

Go up one level in this thread

On April 17, 2001 at 16:07:35, Josť Carlos wrote:

>On April 17, 2001 at 14:51:45, Gian-Carlo Pascutto wrote:
>>On April 17, 2001 at 13:30:22, Vincent Diepeveen wrote:
>>>> Are you sure you spend most of your time in eval? My problem is inCheck()
>>>>since ever. That's where my prog spends most of the time.
>>>>  The good thing is that, everytime I want to improve the speed of my
>>>>program, I know exactly where to focus on :)
>>>>  I suggest you to profile your program to know exactly where the time is
>>>>spend, although probably you've already done this.
>>>>  Josť C.
>>>How can this eat system time anyway?
>>If you dont have any attack information available incheck can be
>>costly. In Sjeng it topped the running profile a long time, though only
>>with 15%-20% of the total time or so.
>>I speeded my incheck/legal_move up greatly by looking at the move last
>>played and figuring out if it could possibly have put the king in check.
>  Exactly. That's what I'm doing right now. But actually my makemove() function
>is about 5000 lines !!! And I still haven't remove half the inCheck() calls !!
>  This is driving me mad, since there're a lot of rare cases that you must take
>into account. Really hard, but I hope it's worth the effort.

what do you do in makemove?

If you do next:

 if( possiblecheck[piece][fromfield][kingfield]
  && scanbetween(piece,fromfield,kingfield) )

i do not see how figuring out whether such a move is a check can cost
more as say 1% system time even in a program getting half a million
nodes a second at a PII450.

Best regards,

>  Josť C.
>>You can apply a lot of tricks to make this very fast.
>>Now it is way down on the profile (>3% or so), and my program became about
>>6% faster. Now need to find a way to get SEE attack info quicker :)

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