Author: Peter Fendrich
Date: 07:23:13 01/17/00
When searching the hash table, I've detected basicly 9 different states. The value from the table is a Lower (L) or Upper (U) bound or Inside (I) it's A/B-window. For each of these we have 3 cases: 1. value <= current Alpha 2. value >= current Beta 3. current Alpha < value < current Beta Combining it all we have: 1L, 1U, 1I, 2L, 2U, 2I, 3L, 3U and 3I For now I'm interested in case and 3U. When we have 3L, we know that the table entry is the lowest possible value and that the current Alpha is lower. To me it seems reasonable to set current Alpha = table value. For 3L this will be: current Beta = table value. That doesn't work well with my program which has a PVS-based alg. When re-searching a move, the A/B-window will be narrowed down in the tree based on the 3L and 3U cases above and a FailHigh together with a cut PV-line will be the result. I have tried to set current Alpha = value-1 and current Beta = value+1 with a somewhat better result but this doesn't "feel" right! Now I've turned the thing off completely and can sleep at night again... Something is wrong here. Comments please! //Peter
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