Computer Chess Club Archives


Search

Terms

Messages

Subject: Re: Problem understanding Craftys output

Author: Uri Blass

Date: 11:30:02 07/19/04

Go up one level in this thread


On July 19, 2004 at 14:13:39, Peter Berger wrote:

>On July 19, 2004 at 14:03:43, Robert Hyatt wrote:
>
>>On July 19, 2004 at 11:55:43, Daniel Clausen wrote:
>>
>>>Hi
>>>
>>>I'm testing the position below with various engines available for Linux and
>>>noticed that Crafty 19.15 prints funny things when failing high.
>>>
>>>[D]3qk3/8/8/8/8/8/PPPPPPPP/RNBQKBNR w - - 0 1
>>>
>>>[snip]
>>>
>>>                9->   3.58  33.23   1. e3 Ke7 2. Qg4 Qa5 3. Nf3 Qa8 4.
>>>                                    Qg7+ Kd6 5. Qd4+ Ke7 6. Ne5
>>>               10     4.43     +1   1. e3!!
>>>               10     5.04     +3   1. e3!!
>>>               10     8.10     +M   1. e3!!
>>>               10    35.02  37.08   1. e3 Ke7 2. Qh5 Kd6 3. Qb5 Qh8 4.
>>>                                    Qb4+ Kd5 5. Qc4+ Kd6 6. Qd4+ Qxd4 7.
>>>                                    exd4 Kd5
>>>
>>>[snip]
>>>
>>>I noticed the "+1" things in previous games but never saw a "+3" or "+M" so far.
>>>I guess the "+3" (simliarly to "+1") means that Crafty got a fail high and knows
>>>that that the move is at least +3 better since that was the window of the
>>>re-search. But what is M? If it's a certain number, why don't print that?
>>>
>>>Sargon
>>
>>
>>+1 means a fail high outside the normal aspiration search window of about .4
>>pawns.  The +1 means we are upping the upper bound to current + 1.00.  The +3
>>means we added another +2 which means we are winning at least a pawn, and maybe
>>more.  +M means we are upping the bound to +Mate, meaning that we are winning
>>more than a piece (more than +3.0).
>
>Should have put this question into the other post. Have these values been tested
>thoroughly?  From watching testgames I regularly saw the +1 in PVs,  but so far
>I have never seen the +3 without being followed by a +M some time later - so
>does this trick really save time over all?

Did you see +3 only in cases that Crafty was already winning or also in
different cases after a big fail?

Uri



This page took 0 seconds to execute

Last modified: Thu, 15 Apr 21 08:11:13 -0700

Current Computer Chess Club Forums at Talkchess. This site by Sean Mintz.