Author: Stuart Cracraft
Date: 19:14:26 09/05/04
Go up one level in this thread
On September 05, 2004 at 19:34:21, Uri Blass wrote: >On September 05, 2004 at 19:14:30, Stuart Cracraft wrote: > >>On September 05, 2004 at 18:30:30, Bas Hamstra wrote: >> >>>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. >> >>Most programs I've heard of have a maximum ply setting beyond which the >>search can't go. >> >>How about you Uri and you Bas? >> >>Stuart > >Movei assumes that the ply is always smaller than 100 >If it is bigger than 100 the program may crash because it does not check if >ply<100 in it's search. > >Practically based on my experience it never get close to 100. > >Uri Well, this is what I have observed with my program allbeit on slow hardware and with extremely short searches. However, I do occasionally feed it the various challenge positions posted by posters on this board and let it run for a few minutes. Usually, 40 or 50 ply is the max ever reached. There is probably a good reason to limit this as out that far it looks rather outlandish. Stuart
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