Author: Robert Hyatt
Date: 12:02:05 10/13/03
Go up one level in this thread
On October 13, 2003 at 12:57:04, José Carlos wrote: >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. Don't fall into his trap. In the q-search, which I _explicitly_ said I was talking about exclusively, there is no "depth remaining" to extend. His comments are, as always, nonsensical. If we were talking about the basic search, then things are a bit different. But I do it my way there for a reason. It guarantees that I _never_ reach the q-search when the side-to-move's king is in check. But we weren't talking about that case in what I wrote and where Vincent responded with a completely random comment.
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