Author: Stuart Cracraft
Date: 16:10:19 03/07/06
Go up one level in this thread
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. Stuart
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