Author: Scott Gasch
Date: 13:08:51 04/24/02
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On April 24, 2002 at 14:34:05, Dann Corbit wrote: >On April 24, 2002 at 04:26:05, Scott Gasch wrote: > >>On April 23, 2002 at 12:40:09, Robert Hyatt wrote: >> >>>1b6/8/8/7p/6k1/6P1/8/6K1 w - - 0 1 >> >>I take it you are not using EGTBs or node recognizers. I turned off EGTB in my >>engine but I cannot turn off the node recognizers... my output looks like this: > >What is a node recognizer? Are you looking for repeats or cycles? Ernst wrote a paper about node recognizers and I implemented it based on my understanding of his paper. Basically at all points in the tree (not just the leaves) the search sends the board configuration to a recognizer function. That function, if the board is simple enough and it has the proper knowledge, sends back a score and a type to the search. For example one of my recognizers says "if you have a rook pawn and the wrong color bishop and the enemy king controls square X then it's a draw". My main recognizer function calls out to the EGTB lookup to hit the tablebases if there are less than 6 men on the board (and EGTBs are not disabled). If there's no help from them it calls the proper recognizer. Most of the time 5-man EGTBs make recognizers useless... but sometimes I skip the EGTB probe (don't want to probe TOO much) but I don't skip the recognizers because they are high-speed (not relying on disk I/O).
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