Author: Robert Hyatt
Date: 08:19:02 11/11/01
Go up one level in this thread
On November 11, 2001 at 04:52:46, Guido wrote:
>On November 10, 2001 at 10:04:39, Robert Hyatt wrote:
>
>....
>>
>>NO. You are still missing the key case. Is an EP possible in the future,
>>not just right now? But what about positions where white has a pawn on e2,
>>and black has a pawn on d7. Any mate-in-N will be wrong if your generator
>>didn't do any EP captures, because there will be many positions where an
>>EP will be possible _somewhere in the future_. And yet your generator produced
>>scores think that if it gets the black pawn to d4 and white plays e4, that black
>>can't take the white pawn. That greatly changes the position. And means any
>>analysis based on positions where EP is _ever_ possible will be wrong.
>>
>
>Thank you very much for your explanation.
>I'll try to make comparisons between results of Nalimov's and my EGTBs in kpkp
>ending for example.
>Probably Nalimov's solution is the only practically possible, also if it
>requests more RAM and some complications in the positions evaluation.
>
>Guido
Here is what I used to do for the old Edwards EGTBs with no EP:
probe=true;
do {
if (pawns are not on adjacent files) break;
if (both pawns have moved) break;
if (one pawn has not moved but other pawn has already passed it) break;
/* ie white pawn on e2, black pawn on d2 or d3 means no EP will ever
be possible */
probe=false;
} while(0);
if (probe) probe EGTBs;
It worked perfectly although it obvously skipped probing some positions that
did have KP vs KP.
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