Author: Stuart Cracraft
Date: 17:08:07 09/05/04
Odd improvement... I had used see within quiescence to discard moves < 0 of see value (losing combinations) and those that didn't make it past a certain margin (futility cutoff / delta pruning). At the time I had added a capability in the move generator when a move is added that scored any capture with see and stored it for later use. This was then used in the quiescence as above for discarding, avoiding using the generate there. But because of having to do the see for each move in the main search, the net result was worse performance on test suite, not better. So I just made a separate routine to keep the see() running completely out of the main search, do it for all capture moves all the time in quiescence but at time move is added to movelist instead of at time move is searched. This resulted in 1% improvement in score: wacnew **** 6.80/23.83 80% 240/300 250.67 73082144 243607/1/291553 0/871282/397085/1606 781/18010090/63447 wacnew with the see() call in movelist routine instead of quiescence, but still used in quiescence **** 6.81/27.35 81% 244/300 249.71 74112552 247042/1/296798 0/854177/1447453/515 821/17298092/99799 Not quite sure why this occurred. There may be some other confounding factor that I just got lucky with when making the change. I looked more carefully and saw a side change I had made was simply to add the "see" score into the mvv/lva and then make that the pre-search score of the move from the move-generation routine. Previously, mvv/lva was used only, unless the global see() use in move generation for all captures for both main search and quiescence search was used. Now, see score is added in, with mvv/lva, in move generation, for all captures but only in quiescence -- see is not used in main search. Anyway, add your see score in like the above and see if you experience a small jump, rather than just using <0 to decide whether to cut. You get the benefit of the sort, helping the move ordering. I speak only to the ones who didn't do this already. Stuart
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