Author: Bas Hamstra
Date: 12:58:39 09/05/04
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On September 05, 2004 at 14:56:14, Uri Blass wrote: >On September 05, 2004 at 14:30:01, Bas Hamstra wrote: > >>>My program has this in relation to checks, all conditionally compilable: >>> >>> 1) all checks-evasions in quiescence, unlimited occurrences >>> 2) all checks-evasions in main search, unlimited occurrences >>> 3) all checking-moves in quiescence, at the first ply of quiescence >>> >>>These are the three extensions. Only #1 and #2 have proved useful. >> >>Impossible. When I did 3) it solved wac141 within one second, using a mate >>extension of a full ply. It takes 30.000 nodes and 6 plies to anounce M6. > >With mate extension of a full ply your search will explode because >there are positions when there are a lot of checks and every reply to check is >a mate threat. Not in my search. But I have taken actions to prevent "stapling" of useless matethreats. I have done a full ply mate-extend in Tao 5.4 without problems. >6 plies to see the mate and only 30000 nodes. >It seems to me hard to believe it espacially when I expect your search with >full ply extension for mate to explode. See above for the explosion. I am not saying a full ply mate-ext is best, but I have used it for years and it worked fine. This is probably also a matter of what your qsearch can do. Mine can solve simple multi-move mates. >Of course checks in the qsearch helps but I still need 8 plies without mate >extensions only to find the move without mate score(it is after I decided to >reduce my evaluation based pruning). Yes, I checked and have the same result without mate-ext. >I will check with enabling mate extensions only in the first 11 plies(no need >to extend after 11 plies to find mate in 6) and check results again. > >>Without it it has a hard time and it takes very long. The point is: if your >>qsearch cannot find a simple mate in one (a capture only qsearch wont) chances >>are you will find this mate a full 3 plies later than necessary. >> >>If you implemented 3) your program should mate-extend like crazy here... >> >>Bas. > >If he implements 3 then his program will crash because it will never get to the >second ply of the qsearch because his qsearch call the main search and not the >qsearch. You are right here. When you do checks on the first q-ply and call the mean search for check-evasions, you will have unlimited checking sequences and that's bad. Bas.
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