Author: Vincent Diepeveen
Date: 07:49:05 01/17/00
Go up one level in this thread
On January 17, 2000 at 10:23:13, Peter Fendrich wrote: >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. Oh i hear a lot of dudes inventing this. It never worked for me. I don't do it in DIEP. There are more difficult ways to ask for trouble... >That doesn't work well with my program which has a PVS-based alg. right. simple insight will provide us also why. suppose your bound from hashtable is n ply search based. Now you search at ply = n-i ply where i > 0. Probably more reasons are there than this... >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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