Author: Stuart Cracraft
Date: 13:37:32 09/05/04
Go up one level in this thread
On September 05, 2004 at 15:58:39, Bas Hamstra wrote: >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. Repetition detection would take care of that. My search terminates and never goes anywhere near the 99 maximum ply setting. Usually at 8, 9, 10, 11 ply it is no more than 4x the nominal main search depth, e.g. 32, 36, 40, 41 -- I don't limit quiescence to that, it just often turns out that way. No unlimited checking sequences noted due to repetition detection and draw return in both mainsearch and quiescence. On the other hand, I am anxious to try a quiescence that does not handoff to main search to get out of check in quiescence. I was hoping to do that this afternoon. Stuart
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