Author: Antonio Dieguez
Date: 22:59:25 01/16/03
Go up one level in this thread
On January 16, 2003 at 23:39:27, Thomas McBurney wrote: >I'm writting my first chess program (as a hobby) and I'm interested in other >peoples opinions on how the quiescence search should work. I'm just trying to >keep it simple at this stage just so I get it working properly, but I may adopt >more complex ideas later on. > >[D]rnb1kb1r/pppp1ppp/4p3/4P1q1/3Pn3/3B4/PPP1QPPP/RNB1K1NR w > >Here is an example of a position being sent to the qsearch for processing (after >Qh4-g5). > >My program (at the moment) is doing the following with the above example I have >provided... > >1. Bxg5, NxG5 - Score= -8.99 > >* At this point do you think my program should say "well, that was decisive, I >should return this score and search no further"? Or is it important to search >other combinations in case it reveals other more important tactics? mmmh the alphabeta window would take care of a failhigh for white. You can certainly disregard the rest of the captures, eval+expected_gain<=alpha, that's futility. >2. Bxe4, Qxc1+, Q-d1, Qxd1, Kxd1 score= 0.14 >3. Bxe4, Qxc1+, Q-d1, Qxb2 score= 0.94 >4. Qxe4, Qxc1+, K-e2, Qxb2 score= 1.19 > >After considering all the above combinations my qsearch returns the score of >-8.99, which looks correct to me. My program would do the same qsearch with minimax. >The rules I'm using at the moment are as follows: >1. capture any peice of higher value in order of highest to lowest value. >2. capture any piece of equal value >3. capture lower valued pieces only if they are not protected >4. if only 1 possible move can be made, regardless of capture or no capture, >then make that move. > >Do you think what I am doing is reasonably sound? Yea why not... > One problem I have come >accross is if for example after Nxf2, the qsearch will not consider Qxf2 because >it is a lower valued piece and it is protected (by the Queen on h4). Oh I see. Well you don't want to do a SEE for simplicity, but seeing if there are other capture to f2 is not complex, also see if the queen is suported by a sliding piece in the right direction. Then you can asume you win the min between the piece_captured and (piece_captured+lowest_piece_defending-capturing_piece), or, more simple, dont look at the lowest_piece_defending and asume you can win the piece captured. Not the cleverest thing but better than how you have it now I bet.
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