Author: Stuart Cracraft
Date: 13:28:19 03/08/06
Go up one level in this thread
On March 07, 2006 at 19:28:44, Dann Corbit wrote: >On March 07, 2006 at 19:10:19, Stuart Cracraft wrote: > >>On March 07, 2006 at 13:58:48, Dann Corbit wrote: >> >>>On March 07, 2006 at 04:39:52, Uri Blass wrote: >>> >>>>On March 07, 2006 at 03:47:06, Dann Corbit wrote: >>>> >>>>>On March 07, 2006 at 03:02:17, Uri Blass wrote: >>>>> >>>>>>On March 07, 2006 at 00:46:27, Dann Corbit wrote: >>>>>> >>>>>>>On March 07, 2006 at 00:41:55, Dann Corbit wrote: >>>>>>> >>>>>>>>On March 07, 2006 at 00:34:48, Stuart Cracraft wrote: >>>>>>>> >>>>>>>>>On March 07, 2006 at 00:31:45, Dann Corbit wrote: >>>>>>>>> >>>>>>>>>>On March 07, 2006 at 00:27:43, Stuart Cracraft wrote: >>>>>>>>>>[snip] >>>>>>>>>>>Very interesting indeed. A clever test. >>>>>>>>>>> >>>>>>>>>>>If one's results do not rotate approximately as described >>>>>>>>>>>for the four positions and you say the evaluation is an >>>>>>>>>>>issue, what kinds of evaluation issues have you seen that >>>>>>>>>>>could explain it?!? >>>>>>>>>> >>>>>>>>>>The most common thing that I see is something that is good for white being >>>>>>>>>>counted as positive for black also on the evaluation. Often, when we are >>>>>>>>>>writing the eval, we are thinking from the perspective of white. And so if we >>>>>>>>>>are not very careful, we may invert the sign of some evaluation component and >>>>>>>>>>count something that is good for white as something that is good for black (or >>>>>>>>>>vice versa, though the reverse is seen less often for some reason). >>>>>>>>>> >>>>>>>>>>There are, of course, many other possible causes besides that. >>>>>>>>> >>>>>>>>>A good point. I try to avoid that by always doing things from the >>>>>>>>>side on move, almost always. There are a few in there however with >>>>>>>>>respect to white and black specifically, but they are then folded >>>>>>>>>together with the stm variable and stm^1 which translate to white/black >>>>>>>>>or black/white depending on who's on move. I could try this: rerun >>>>>>>>>your rotation test with successively less in the evaluation table >>>>>>>>>until nothing but material and see what happens. >>>>>>>> >>>>>>>>Right. If you have divided off the eval components, you could binary search >>>>>>>>until you find the problem component. >>>>>>>> >>>>>>>>Now, we do not know for sure that it is an eval sign problem. However, the fact >>>>>>>>that the records are similar in pairs makes it very suspicious. >>>>>>> >>>>>>>I guess that when you have gotten your eval symmetrical, you will miss less than >>>>>>>ten problems on WAC. >>>>>> >>>>>>I think that you are wrong here. >>>>>>Stuart may have evaluation bugs but his main problem is the search. >>>>> >>>>>I think it likely that it is both. >>>>> >>>>>Given: >>>>>5rk1/2p4p/2p4r/3P4/4p1b1/1Q2NqPp/PP3P1K/R4R2 b - - bm Qg2+; id "-rotXTDa.1"; >>>>>1kr5/p4p2/r4p2/4P3/1b1p4/pPqN2Q1/K1P3PP/2R4R b - - bm Qb2+; id "-rotXTDg.1"; >>>>>r4r2/pp3p1k/1q2nQpP/4P1B1/3p4/2P4R/2P4P/5RK1 w - - bm Qg7+; id "-rotXTDc.8"; >>>>>2r4r/k1p3pp/PpQn2q1/1B1P4/4p3/R4P2/P4P2/1KR5 w - - bm Qb7+; id "-rotXTDe.8"; >>>>> >>>>>When I changed to material only eval, here is the result: >>>>> >>>>>st 5 >>>>>ts >>>>>position file? [wac.epd] rot.epd >>>>># of test positions to test? 4 >>>>>maxtime = 500 >>>>>Interrupt current ply and return move at timeout >>>>>Testsuite: rot.epd 4 positions >>>>>*** Problem Solution(s): Qg2+ (bm) >>>>>[D] 5rk1/2p4p/2p4r/3P4/4p1b1/1Q2NqPp/PP3P1K/R4R2 b - - bm Qg2+ >>>>>*** Problem Solution(s): Qg2+ (bm) >>>>>-- ** -- ** -- BR BK ** >>>>>** -- BP -- ** -- ** BP >>>>>-- ** BP ** -- ** -- BR >>>>>** -- ** WP ** -- ** -- >>>>>-- ** -- ** BP ** BB ** >>>>>** WQ ** -- WN BQ WP BP >>>>>WP WP -- ** -- WP -- WK >>>>>WR -- ** -- ** WR ** -- >>>>>mv 1 stage 0, black to move, computer plays black >>>>>hash=62305c813f5fad4 >>>>>pawnhash=3da7edf6c1ba87ea >>>>>0 0 0 0 0 0 >>>>>Alpha=-400 Beta=400 Maxdepth=9999999 MaxTime=500 xboard=1 >>>>>Ply Score Time Nodes PV >>>>>1. 40 3 12 c6d5 e3d5 >>>>>1. 900 5 74 f3g2 e3g2 >>>> >>>>Qg2+ is a sacrifice so it is not logical so if the computer choose it at depth 1 >>>>then it means that there is a serious bug. >>> >>>It may find the result by quiesce(). >>> >>>I think you are probably right about search problems also. >>> >>>However, having errant terms in his eval, and having search stability problems, >>>and yet still solving 3/4 of WAC, I suspect he will make rapid progress once he >>>irons out some simple details. >> >>That is hopeful, but... >> >>Unfortunately, these issues have cost me a substantial fraction of >>my life and I need to move to the next phase in the development but >>will sit on this issue until I get some sort of reasonable forward >>movement. >> >>While I am willing to pay significant money directly for consultation that >>produces a significant forward advance, I thought the idea of contributing to >>the board more palatable since I wouldn't know which volunteer (if any) to pick. >>Besides it's cheaper. >> >>I should recreate Bob's evtest/flip/flop that can be used for any >>position to check and compare the evaluations of any given EPD suite >>and then run it on WAC itself. A further version could narrow it down >>to the function and then the term within the function. >> >>That is something that does not require a lot of understanding or new >>kind of thinking on my part to get to somewhere useful. I'm not tired >>of thinking, just tired of banging my head against a wall. >> >>My goal is simply to get a reasonable tactictian before the next phase >>which I doubt will be as hard. > >The VB program I sent to you by Les Fernandez does exactly that. You can >trivially do it also in C. Thanks.
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