Author: Ed Schröder
Date: 10:52:39 12/29/01
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On December 27, 2001 at 15:47:33, Uri Blass wrote: >On December 27, 2001 at 14:46:44, Severi Salminen wrote: > >>>The search techniques are similiar to TSCP except >>>limiting the qsearch to 7 plies >>> >>>I believe that it is illogical to let the qsearch to explode >>>and it is also illogical to let it to explode only when the >>>program search deeper. >>> >>>Qsearch is selective search and if you search many plies >>>forward then you cannot trust your score and >>>if you cannot trust your score there is no logical reason >>>to waste more nodes in order to find a score and >>>it seems better to me to save time and to >>>return static evaluation. >> >>In my opinion, on the other hand, it is illogical to actually limit qsearch. >>1. qsearch will termainate automatically (and usually quite quickly) when there >>are no captures left: so no need for depth limiting. > >There are practical cases when the qsearch include >hundreds of nodes > >The following position happens in the tree of TSCP of the >initial position > >[D]r1bqkbnr/ppp2ppp/2n5/3pp3/3PP3/2N5/PPP2PPP/R1BQKBNR w KQkq - 0 3 > >The qsearch includes the following captures >1.exd5 exd4 2.dxc6 dxc3 3.Qxd8+ Kxd8 4.cxb7 cxb2 5.bxa8Q?? > >The qsearch misses the move Bg5+ that is winning for white. Yes, that's true QS will miss Bg5+ But realize the goal of QS, that is: an accurate evalution of the leaf because eval can't do that for you. You can of course include check moves in QS (I do) and it will see Bg5+ too but be prepared the QS to explode. Ed
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