Author: Tim Foden
Date: 11:46:38 10/05/01
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On October 05, 2001 at 13:24:57, Koundinya Veluri wrote: >On October 04, 2001 at 07:03:14, Tim Foden wrote: > >>Hi All, >> >>I decided that I would add a 2nd SEE to GLC to check whether GLC's SEE was >>working. I actually ported GCP's Sjeng SEE (that was posted to the forum a >>while ago). >> >>Both SEE routines now agree in most curcumstances, but one's like the following >>have cropped up (where they disagree): >> >>[D]5rk1/1pp2R1p/p1pb4/6q1/3P1p2/2P4r/PP1BQ1P1/5RKN w - - 2 0 >> >>This can be evaluated in 2 ways... >> >>(1) BxP (+1000) BxB (-3500) R1xB (+3500) QxR (-5500) RxQ (+10000) RxR (-5500) >>.........+1000.......-2500........+1000.......-4500........+5500...........0 >> >>>>> value = 0 >> >>(2) BxP (+1000) BxB (-3500) R7xB (+3500) RxR (-5500) RxR (+5500) QxR (-5500) >>.........+1000.......-2500........+1000.......-4500.......+1000.......-4500 > >My SEE doesn't differentiate between the two different methods. It actually >returns -200 (-2000 in your case) and when I traced it, I found this: > >BxP (+100) BxB (-300) >.....+100.......-200 > >It stops there because it sees that capturing with a rook would lead to more >losses (it assumes the second case, where black captures with the rook first). >So the second case should really be terminated after BxP BxB, which would result >in a score around -200 (or -2000). Ah, but if w keeps on capturing, black must always reply, and the end result for both black and white is a value of 0, which is better than your -2 (or GLCs -2.5). I.E.: BxP (+1000) ... +1000 if B doesn't re-capture, he is -1000. BxB (-3500) ... -2500 if W doesn't re-capture, he is -2500. R1xB (+3500) ... +1000 if B doesn't re-capture, he is -1000 QxR (-5500) ... -4500 if W doesn't re-capture, he is -4500. RxQ (+10000) ... +5500 if B doesn't re-capture, he is -5500 RxR (-5500) ... 0 the end. Because the final score is 0, once the sequence is started, both sides must continue, else they will do worse than 0. Cheers, Tim.
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