Author: Ralph E. Carter
Date: 06:12:05 12/24/98
Go up one level in this thread
>>Posted by James T. Walker on December 22, 1998 at 19:47:21:
>>
>>Bob I hope you see this and can explain. This is the Crafty 15.20 inside of
>>Nimzo 99 and inside Junior appears to work the same way. Notice the times it
>>takes for Crafty to move. When this is run under Winboard Crafty plays the
>>entire variation in only a few seconds. Notice Crafty takes 72 seconds to make
>>the Mate in 1 move. Crafty searches 10 ply for that move but notice that is
>>typical of all the moves. It's a mate in 7 I created several years ago (18) to
>>test some of the old dedicated chess computers.
>>
>>Event "?"]
>>[Site "?"]
>>[Date "????.??.??"]
>>[Round "?"]
>>[White "Crafty 15.20"]
>>[Black "?"]
>>[Result "*"]
>>[Annotator "Crafty 15.20"]
>>[SetUp "1"]
>>[FEN "1k6/1P3p2/K7/8/8/8/7P/8 w - - 0 1"]
>>[PlyCount "13"]
>>
>>{59392kB, nzbook.CTG. PentiumII
>>} 1. Kb6 {#7/12 46} 1... f5 {11} 2. h4 {#6/14 31} 2... f4 {1}
>>3. h5{#5/12 40} 3... f3 {1} 4. h6 {#4/11 39} 4... f2 {1}
>>5. h7 {#3/11 38} 5... f1=Q {27} 6. h8=Q+ {#2/10 11} 6... Qf8 {3} 7. Qxf8# {#1/10
>>72} *
>>
>>Jim Walker
>
Reply from Dr. Hyatt:
>No way to explain that. One point is that after I do a search and play a move
>that leads in mate, the next search terminates as soon as a shorter mate is
>found (to be sure I am making progress). But once I find a mate in 1 I should
>play it instantly unless something else is going on. It is certainly possible
>that the "new" command clears enough things to break this as well...
My findings:
Here are the results I get for this problem: (PII-300)
Mate in: Time:
#7/12 34
#6/14 15
#5/12 15
#4/11 15
#3/9 14
#2/9 13
#1/9 25
Note that even the mate in one takes 25 seconds.
Wanting to be CERTAIN, I ran it again with a different time control, with
similar results.
THE MATE IN ONE, WHICH WOULD BE PLAYED INSTANTLY UNDER WINBOARD, TAKES 25
SECONDS UNDER THE CHESSBASE INTERFACE.
When the same problem is given to Junior 5, same hardware, same time control,
after rebooting, its results are
Mate in: Time:
#7/18 2
#6/12 0
#5/12 0
#4/9 0
#3/9 0
#2/3 0
#1/3 0
UNDER THE CHESSBASE INTERFACE, JUNIOR 5 SOLVES THE MATE IN ONE INSTANTLY, AS IT
SHOULD.
When this problem was pointed out on rgcc, the reply from the programmer of
Junior 5 was (I paraphrase)
"This problem was invented to explain a bad result. But it has no relationship
to anything happening in the real world."
When I asked him "If it were YOUR program performing worse than expected, would
you want people to know why?" He did not reply.
The hashtable of Hiarcs 6 also gets cleared between moves. This presumably
effects its results.
I think everyone should know about it. That is all.
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