Author: Uri Blass
Date: 09:57:22 10/03/03
Go up one level in this thread
On October 03, 2003 at 12:47:23, Uri Blass wrote: >On October 03, 2003 at 12:13:13, Anthony Cozzie wrote: > >>On October 03, 2003 at 12:03:49, Uri Blass wrote: >> >>> >>>I can detect every big threat by adding a special search after making null move. >>> >>>For example if I like to detect threats of at least 2.2 pawns I can do >>>val=-alphabeta(depth-4,-beta+219,-beta+220,...) >>> >>>if (val<=beta-220) >>>threatmove[ply-1]=1; >>>//ply-1 because I still did not undo the null move. >> >>small error here: beta should be replaced by eval, or you will have massive >>instability problems. > >If I am a queen down in the search and I threat to win a bishop then I do not >consider it as a threat because a threat is a threat relative to beta. > >I believe that Tord does the same(he replied that your example of threating the >queen twice by sacrificing material is solved by extending only big threats so >if you sacrifice a rook and a bishop the threat on the queen is not a big >threat). > >I think that the idea that an extension should not be dependent on beta is a bad >idea. >It is better to have stronger engine with stability problems and not >weaker engine without them. > >I prefer even not to care about using hash tables for pruning because my >experience told me that I cannot get significant gain there easily(I have a lot >of stuff that means that pruning or extension is not defined only by the >position). > >Uri I can add that I believe that there is also a lot to improve in movei without using hash tables for pruning(otherwise I could prefer to try to use it for pruning inspite of the problems). Uri Uri
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