Author: José Carlos
Date: 09:57:04 10/13/03
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On October 13, 2003 at 12:03:32, Vincent Diepeveen wrote: >On October 13, 2003 at 11:31:11, Robert Hyatt wrote: > >>On October 13, 2003 at 09:29:47, Vincent Diepeveen wrote: >> >> >>> >>>there are very big differences. >>> >>> >> >>There isn't a big difference if you are only talking about the q-search. >> >>If you do a check, you have to get out and that extends. If you extend >>on the check you don't extend when you get out and that extends. >> >>It is different in the normal part of the search, because if you extend on >>a check you increase depth by one now. You might reach the q-search if you >>wait to extend when you escape check. but in the q-search I don't see how it >>is a "big difference". > >You don't have to apologize for not knowing basic tree math, you're excused. >Had seen already in crafty code that it was done wrong there. > >Yet i had already posted years ago at CCC that if you extend when being checked, >that this is better than when giving the check. > >What delivers more cutoffs for the hashtable: > >A) >Re5+ (5 ply remaining) >Kf7 (5 ply remaining) >Rxa5 (4 ply remaining) > >B) >Re5+ (5 ply remaining) >Kf7 (4 ply remaining) >Rxa5 (4 ply remaining) > >If you can answer that question then you'll know the answer to the basic tree >searching question. > >Best regards, >Vincent Do you cutoff in moves or in positions? If you cutoff in positions, then you have: Extend check: A -Re5+-> B -Kf7-> C -Rxa5-> D 5 5 4 3 (depth remaining) Extend out-of-check: A -Re5+-> B -Kf7-> C -Rxa5-> D 5 4 4 3 (depth remaining) So the only difference is position B. In the first case you store depth 5 in the hash table, in the sencond case, 4. In principle it seems that extending checks would give more cutoffs due to hash table, but to get to position B you need a checking move, which would extend (increase remaining depth) in the first case, and not extend in the second. The result seems to be that both will work the same, except for leaf nodes, as Bob pointed. José C.
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