Author: Mike Byrne
Date: 16:10:09 07/24/02
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On July 24, 2002 at 17:14:48, Nolan Denson wrote: >Ok from some post that Mike made i realize that i can change the extension >values of crafty .... but I am still not sure whats going on. > >As you can see from below the singular ext for Matrix is set at .58 ... I am >not sure if this is bad or good ... So if i wanted to change this value what >would the command be or where in the code does the rest of this get change at. > >I notice that mike changes these values via the crafty.rc file. Where are these >values actually effecting crafty ?? Which part of the code ?? Then if anyone has >an understanding of the code for singular extension and know where those values >are ... please post also. > >Like i said I am not a programmer ... (but I am learning alot about it by doing >these kind of things) .... I want to change the .58 to a different value, and >run some test to see what happens. At the end of this message i posted the code >for singular extensions as well. Also do you guys that know about this think >that the .58 is too low or too high? Mike changes his values via the following >commands : via the crafty.rc > >booster 76 76 225 >ext in 1 >ext th 1 >ext one .75 >ext pawn .75 > > >one-reply extension..................0.75 >in-check extension...................1.00 >recapture extension..................0.75 >pushpp extension.....................0.75 >mate thrt extension..................0.75 >singular extension...................0.58 >one-reply extension..................0.75 >in-check extension...................1.00 >recapture extension..................0.75 >pushpp extension.....................0.75 >mate thrt extension..................0.75 >singular extension...................0.58 >one-reply extension..................0.75 >in-check extension...................1.00 >recapture extension..................0.75 >pushpp extension.....................0.75 >mate thrt extension..................0.75 >singular extension...................0.58 >one-reply extension..................0.75 >in-check extension...................1.00 >recapture extension..................0.75 >pushpp extension.....................0.75 >mate thrt extension..................0.75 >singular extension...................0.58 > > >Matrix v99.99 (2 cpus) > >White(1): ext >one-reply extension..................0.00 >in-check extension...................0.00 >recapture extension..................0.00 >pushpp extension.....................0.00 >mate thrt extension..................0.00 >singular extension...................0.58 > > Hi Nolan - It's easy to change the extensions via the crafty.rc file. There was a change fron Crafty 17 to Crafty 18 ... Crafty 17.xx used the following ext in (in check) ext th (mate threat) ext rec (recapture) ext p (pawn push) ext one (one response) Crafty 18.xx ext ch (in check) ext ma (mate threat) teh other are the same in Crafty 18.xx The allowables value are from 0 to 1. Crafty uses partial extensions - so value of 1 will extend 1 ply if the condition is met. A value of .5 will extend a 1/2 ply. Crafty also cuts extension in half when the increment depth is > 2 ply. Generally , the default values have been .75 or 3/4 ply. I usually prefer the either the in-check or threat (or both to be set at 1). If you start adding extension, you generally have to lower the number. Very high numbers may do well in certain positions - but it can do horrible in other positions if there is a "lot" going on. I used to be very high on the recapture extension, but with the faster hardware and the quiesce rountine - I am not convinced it always needed - but there are certainly some positions that it helps - in other positions it just helps to blow up the search. There is no one right answer - I usually prefer them to be higher. Mike
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