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Subject: Re: perft and underpromotions

Author: Tim Foden

Date: 11:32:35 04/24/03

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On April 24, 2003 at 14:17:06, Uri Blass wrote:

>On April 24, 2003 at 13:58:10, Will Singleton wrote:
>
>>On April 24, 2003 at 13:37:52, Uri Blass wrote:
>>
>>>On April 24, 2003 at 13:33:16, Will Singleton wrote:
>>>
>>>>Hi,
>>>>
>>>>I'm looking for a program that does perft without underpromotions.  Thanks.
>>>>
>>>>Will
>>>
>>>modifying movei to do perft without under promotions is easy only changing one
>>>line in the source code.
>>>
>>>Why do you need it?
>>>
>>>Uri
>>
>>I don't do underpromotions.  I'd appreciate if you could send me the modified
>>movei, thanks very much!
>>
>>Will
>
>I will send you it in the next few hours.
>
>I am now busy in writing my evaluation in a more convenient way to change and
>testing for bugs by asking the program to compare new evaluation with old
>evaluation and when they do not agree I know that I have bug in one of my
>evaluation because they are supposed to be the same.

One of the great ways of catching bugs in the evaluation is to make a random
position, and "mirror" it.  I.E. flip the board vertically, and change the
colours of all the pieces to the opposite colours, and change the side to move.
The two boards should have the same evaluation.  If they don't there's usually
something wrong.

Repeat the test something like 100000 times.

Cheers, Tim.

P.S.  Don't forget to mirror any castling rights or the e-p square if you
randomly generate them.




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