Author: Uri Blass
Date: 08:44:06 11/13/03
Go up one level in this thread
On November 13, 2003 at 11:29:18, Daniel Clausen wrote: >On November 13, 2003 at 11:10:53, Uri Blass wrote: > >>On November 13, 2003 at 10:53:22, Daniel Clausen wrote: >> >>>On November 13, 2003 at 10:13:34, Uri Blass wrote: >>> >>>>On November 13, 2003 at 09:44:22, Daniel Clausen wrote: >>>> >>>>>On November 12, 2003 at 18:40:32, Peter Kappler wrote: >>>>> >>>>>[snip] >>>>> >>>>>>>I get an average of better than 90%. It takes tuning. Work on killers and >>>>>>>history pays off. Make sure you search bad captures before other moves also. >>>>>>>Taking capture out of killers gave me a boost also. >>>>>>> >>>>>> >>>>>>Hmmm, I think I do bad captures at the end, and as I recall it was a clear win. >>>>> >>>>>IIRC, for most people trying bad captures at the end was better with SEE, but >>>>>worse with MVV/LVA. >>>>> >>>>>Sargon >>>> >>>>How do you know that a capture is bad with MVV/LVA? >>> >>>When someone uses SEE, a capture is bad when the SEE-value for it is negative. >>>When someone uses MVV/LVA, a capture is bad when the MVV/LVA-value for it is >>>negative. >>> >>>It's that simple. :) >>> >>>Sargon >> >>It is not so simple. >> >>By this definition every pawn capture by knight,bishop,rook,queen,king is a bad >>capture. >> >>It does not make sense so it does not make sense even to try to put it after non >>captures. >> >>You can have a function to detect part of the captures as bad captures and also >>use MVV/LVA for the captures that you do not detect as bad. >> >>The function that detect bad captures is not SEE because SEE gives you the >>expected value of the capture and not only the information if the capture is >>good or bad. >> >>SEE can order QxN before QxQ when both are good captures when the special >>function does not do it. >> >>In that case the question if to put bad captures before history moves or not to >>do it is dependent on the definition of bad capture. >> >>Uri > > >I retract everything I said in this thread. :) > >I still had the (false) idea in my head that to calculate the score of a capture >in MVV/LVA, you subtract the value of your piece from the value of the captured >piece, which leads to the problems you pointed above. > >But I guess MVV/LVA just means that the order of captures to try is > >PxQ, B/NxQ, RxQ, QxQ, KxQ, PxR, B/NxR, RxR, QxR, KxR etc > >With this definition there's simply no way to distinguish between good and bad >captures. > >Sargon This is exactly the way that people use MVV/LVA but in order to do it they use scores. I have g->index = (piece(to) * 8) - piece(from); I have pawn=0,knight=1,bishop=2,rook=3,queen=4,king=5 These scores mean that I have exactly negative scores for NXP,BxP,RxP,QxP,KxP Uri
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