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Subject: Re: Very strange crafty analysis ( I think) with a simple mate

Author: Robert Hyatt

Date: 08:01:50 06/10/02

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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...



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