Author: Robert Hyatt
Date: 07:24:13 12/24/98
Go up one level in this thread
On December 24, 1998 at 08:44:03, Ralph E. Carter wrote:
>On December 23, 1998 at 09:05:57, Robert Hyatt wrote:
>
>>On December 23, 1998 at 04:24:09, Ralph E. Carter wrote:
>>
>>>On December 23, 1998 at 04:20:43, Alois Ganter wrote:
>>>
>>>>On December 23, 1998 at 03:17:29, Ralph E. Carter wrote:
>>>>
>>>>>Do you know that engines under Fritz and Junior have their hashtables cleared
>>>>>before every move? And that this has a disproportionate effect on those engines
>>>>>that intelligently save information between moves, like hiarcs and crafty?
>>>>>
>>>>>If nobody cares about questions such as these, I am leaving.
>>>>
>>>>I mailed Chessbase the question last week and they told me to try this
>>>>experiment with Crafty as prove that it is decision of the engine alone what to
>>>>do with hash tables: Take the second move of a position and let Crafty calculate
>>>>some time. Then clip the analysis with search info from the search window to
>>>>Notepad. Then go to the first move and let calculate for some time. Then go
>>>>again to the second move and let calculate. Then clip analysis and compare with
>>>>the first clip. Now the Crafty engine takes 25% less kN to find the same lines.
>>>>I tried with the new 16.2 version from Chessbase download and it is right. And
>>>>they say 16.2 is much stronger because Bob Hyatt corrected a problem in hash
>>>>management.
>>>>
>>>>The Doctor? engine makes the same effect.
>>>>
>>>>Alois
>>>
>>>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
>>
>>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...
>
>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
>
what is that depth stuff above? I don't do "7/12" type searches and have no
idea what that means nor where it is coming from. Or is that "mate in 7 found
at ply=12"??
I don't know how to make crafty take 25 seconds to find a mate in 1, nor
why it would search to depth 9 to do this. it almost looks like it has been
told that there is a *shallower* mate that has already been found, and it is
continuing to search because I won't quit on an iteration until I find a mate
at least 1 move quicker than the last mate found...
It's definitely broken, although I have no idea why...
>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.
Something is different. question is, what?
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