Author: Les Fernandez
Date: 11:20:54 06/10/02
Go up one level in this thread
On June 10, 2002 at 14:10:17, Andrew Williams wrote: >On June 10, 2002 at 13:44:26, Les Fernandez wrote: > >>On June 10, 2002 at 13:15:55, Andrew Williams wrote: >> >>>On June 10, 2002 at 11:18:25, Les Fernandez wrote: >>> >>>>On June 10, 2002 at 11:01:50, Robert Hyatt wrote: >>>> >>>>>On June 10, 2002 at 03:22:55, Andrew Williams wrote: >>>>> >>>>>>On June 10, 2002 at 00:18:51, Les Fernandez wrote: >>>>>> >>>>>>>On June 10, 2002 at 00:02:39, Robert Hyatt wrote: >>>>>>> >>>>>>>>On June 09, 2002 at 23:45:38, Les Fernandez wrote: >>>>>>>> >>>>>>>>>I rarely come across strange output using Crafty but this position doesnt seem >>>>>>>>>to work right. The ce after analysis I think should be -32765 but in fact it is >>>>>>>>>reporting a "0"??? Either I am dead tired or something is screwy. Would >>>>>>>>>somebody using Crafty run this epd string? It is a very simple mate and I cant >>>>>>>>>seem to find the problem. Its probably just late <S>. >>>>>>>>> >>>>>>>>>Here is Crafty analysis: >>>>>>>>> >>>>>>>>>rnb4k/5r2/2p1p1Q1/pp3pP1/3P4/b2B1KP1/1PPB4/7R b - - acd 1; acn 1; acs 1; ce 0; >>>>>>>>>pv Rh7; >>>>>>>>> >>>>>>>>>The pv appears to be right but the ce value is dead wrong!! >>>>>>>>> >>>>>>>>>If you find the same results can someone please explain the nature of this? >>>>>>>>> >>>>>>>>>[D]rnb4k/5r2/2p1p1Q1/pp3pP1/3P4/b2B1KP1/1PPB4/7R b - - >>>>>>>>> >>>>>>>>> >>>>>>>>>Thanks >>>>>>>> >>>>>>>>Can you describe _exactly_ how you produced that? IE post the epd file >>>>>>>>you used, etc... >>>>>>>> >>>>>>> >>>>>>>EPD Kit revision date: 1996.04.21 >>>>>>>unable to open book file [./book.bin]. >>>>>>>book is disabled >>>>>>>unable to open book file [./books.bin]. >>>>>>>search time set to 180.00. >>>>>>>hash table memory = 48M bytes. >>>>>>>pawn hash table memory = 10M bytes. >>>>>>>Crafty 18.9 vs ferret >>>>>>>kibitz Hello from Crafty v18.9! >>>>>>>pondering enabled. >>>>>>>play best book line after search. >>>>>>>EGTB access enabled >>>>>>>using tbpath=./TB >>>>>>>4 piece tablebase files found >>>>>>>1406kb of RAM used for TB indices and decompression tables >>>>>>>PFGA: EPD record: 1 >>>>>>> >>>>>>>The exact epd string that was in epd.epd was: >>>>>>> >>>>>>>rnb4k/5r2/2p1p1Q1/pp3pP1/3P4/b2B1KP1/1PPB4/7R b - - >>>>>>> >>>>>>>And the epd.out file was: >>>>>>> >>>>>>>rnb4k/5r2/2p1p1Q1/pp3pP1/3P4/b2B1KP1/1PPB4/7R b - - acd 1; acn 1; acs 1; ce 0; >>>>>>>pv Rh7; >>>>>>> >>>>>>> >>>>>>>The analysis report can be found in my original post here. This one puzzles me >>>>>>>too Bob but I could not rule out that its late <S>. If you need any additional >>>>>>>info let me know. >>>>>>> >>>>>>>Thanks >>>>>> >>>>>>Is this because Black has only one move? In my program, if there's only one move >>>>>>available *during a game* it only searches to depth 4. For testing epd >>>>>>positions, it searches normally, even if there is only one move. >>>>>> >>>>>>Andrew >>>>> >>>>> >>>>>That might be the reason. With only one move, the epd code in Crafty might >>>>>not do a search at all, and that would leave the score unchanged from the last >>>>>epd position perhaps... >>>> >>>>Um I am not sure that is what is going on here, let me explain. What I did was >>>>I took an epd position that reported a mate sequence and then made the pv moves >>>>and then created all the following epd positions that eventually led to the >>>>reported mate based on the pv sequence from the first position. Following is >>>>the results of Crafty which ran the epd's that I created based on the pv line >>>>from the first position: >>>> >>>>rnb4k/5r2/2p1p1Q1/pp3pP1/3P4/b2B1KP1/1PPB4/R7 w - - acd 4; acn 10909; acs 1; ce >>>>32764; pv Rh1+ Rh7 Rxh7#; >>>>rnb4k/5r2/2p1p1Q1/pp3pP1/3P4/b2B1KP1/1PPB4/7R b - - acd 1; acn 10909; acs 1; ce >>>>0; pv Rh7; >>>>rnb4k/7r/2p1p1Q1/pp3pP1/3P4/b2B1KP1/1PPB4/7R w - - acd 4; acn 7328; acs 1; ce >>>>32766; pv Rxh7#; >>>>rnb4k/7R/2p1p1Q1/pp3pP1/3P4/b2B1KP1/1PPB4/8 b - - acd 1; acn 1; acs 1; ce >>>>-32767; pv; >>>> >>>>As you can see the second epd string reports a "0" but the one before it and >>>>after it are in fact reporting a value. If your thought "With only one move, >>>>the epd ..... " is correct then why would the last epd position which is the >>>>actual final move show a ce of -32767 ??? Any other thoughts Bob? >>>> >>>>Thanks >>> >>>I think the explanation is correct. The only position you listed which has >>>*exactly* one legal move is the second one, the one where crafty reports 0. The >>>problem is probably that as a way of saving time in games, many programs just >>>make the move without searching it (because there's no choice). For the last >>>position, there are *zero* legal moves. Presumably crafty treats this as a >>>special case as well (my engine does). If there are no legal moves and the side >>>to move is in check my engine returns -M00. If it's not in check, it returns >>>DRAWSCORE. I can't be sure if this applies to crafty too, but I think it's >>>consistent with the original explanation. >> >>Hi Andrew, >> >>I see what you are saying but doesn't this pose a problem. ie suppose I have an >>engine which is doing some type of lookup and sees the ce=0 versuses a mate >>announcement. If what you are saying is correct does that mean we will never >>see a ce value = -32765 ??? In the past I know I have gone through millions of >>epd strings from various sources with the intention of extracting only those epd >>strings that are end in mate. I look up ce values and only keep those positions >>that have an abs(ce)>=32000. How do I get around this delemna? > >I think it depends on the engine that created the epd strings. For example, mine >produces this for the problem position above: > >rnb4k/5r2/2p1p1Q1/pp3pP1/3P4/b2B1KP1/1PPB4/7R b - - acd 13; acn 1657088; acs >10; ce -32765; fmvn 1; hmvc 0; id "fernandez.epd.0001"; pm Rh7 ; pv 1...Rh7 >2.Qxh7 ; > >But I guess it's up to the individual programmer how to handle these cases. If >you're not proficient in C yourself, perhaps you might ask if anyone else wants >to make necessary change to crafty for you? > >Andrew > >PS I've got about 4500 of these from PM's games if you want them. I should warn >you that they may not all be correct. Hi Andrew and thanks for the feedback. As far as these 4500 games go the research I am doing depends on the information to be right. Since some may be wrong let me think about it and get back to you. I think it is important to include the right ce value since reproting a ce=0 suggests the likely hood of a drawn position. Once again thx for the feedback, Les
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