Author: Bas Hamstra
Date: 15:30:30 09/05/04
Go up one level in this thread
On September 05, 2004 at 17:02:49, Uri Blass wrote: >On September 05, 2004 at 16:37:32, Stuart Cracraft wrote: > >>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 > >I guess that you did not search the right positions or did not search deep >enough to get the 99 plies > >there are positions when there can be easily more than 99 plies of checks with >no repetition. > >Uri I have the same experience. Bas.
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