Author: Robert Hyatt
Date: 19:14:20 10/29/98
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On October 29, 1998 at 19:08:53, John Coffey wrote: >On October 28, 1998 at 08:58:05, Robert Hyatt wrote: > >>On October 27, 1998 at 01:35:31, James Robertson wrote: >> >>>On October 26, 1998 at 17:15:56, John Coffey wrote: >>> >>>>On October 26, 1998 at 02:10:37, vincent dichiacchio wrote: >>>> >>>>>my question is how programs deal with the possibility of a great non capture >>>>>move in the middle of a series of captures in a quiescence search. if the >>>>>quiescence score ignores that non capture, the score is faulty at best. >>>>>vince >>>> >>>> >>>>How is Q search any different from extending captures out? Could someone >>>>please define Q search for me? >>>> >>>>John Coffey >>>The q-search is just that; a minimax search that only evaluates capture moves >>>(maybe also pawn pushes or check evasions). This is a major simplification, as >>>there are several big differences from the normal minimax search. >>>I am still trying to think of how to explain them....... um...... er..... can >>>someone like Bob or Ernst help here? >>> >>>James >> >> >>the two main differences between normal search and q-search: >> >>1. in the q-search, we initialize alpha to Evaluate() which gives us the >>opportunity to either (a) make any move we want to or (b) stop the search at >>this point and take the static evaluation (this is the "stand pat" option). >> >>The point is that you might not have a good capture to make. This lets you >>say "should I stop the captures here and accept the score/material balance on >>the board, or should I capture something here?" >> >>2. in the q-search we generally exclude some moves. IE in crafty I exclude >>all non-captures right up front. Then I exclude captures that seem to lose >>material based on the SEE procedure. >> >>Other than those two things, they are similar. No real need to do repetition >>checking in the qsearch if you only do captures, for example. Perhaps a few >>other things like the 50-move rule also don't apply, depending on what you >>exclude... > >Does Q-search come before or after the capture search? I.e. do you do >a full search, and then extend that with a Q seach and then extend that will >a capture search? Or are they the same? > >John Coffey In the above context, qsearch == capture search...
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