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question about symmertic evaluation
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Uri Blass



Joined: 08 Mar 2006
Posts: 6016
Location: Tel-Aviv Israel
PostPost subject: Re: question about symmertic evaluation    Posted: Wed May 23, 2007 10:04 pm Reply to topic Reply with quote
bob wrote:
Gerd Isenberg wrote:
One idea is to avoid the asymmetrical arithmetical shift right 3 at all and to mul all other eval aspects by 8. You may add 7 if the value to shift arithmetical right 3 is negative, but this is of course more expensive.
Code:
symmetrical arithmetical shift right 3 ::= (x + ((x>>31)&7)) >> 3
or with respect to the value range:
Code:
symmetrical arithmetical shift right 3 ::= (x + ((unsigned)x>>29)) >> 3

The common approach seems to score and aggregate from white resp. black point of view and keep both values in evalScore[2] to divide both before the final difference for color's point of view:
Code:
posEval = (evalScore[color]>>3) - (evalScore[color^1]>>3);

Gerd


I'd be willing to bet that a plain divide will not noticably affect his overall search speed. And it will solve this correctly.


thanks

It seems that replacing some >> by / solves the problem
of anti-symmetric evaluation and now at least for the wac positions my evaluation is symmetric between white and black(did not check symmetry between left and right)

Uri
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Subject Author Date/Time
question about symmertic evaluation Uri Blass Wed May 23, 2007 7:53 pm
      Re: question about symmertic evaluation Uri Blass Wed May 23, 2007 8:45 pm
      Re: question about symmertic evaluation Gerd Isenberg Wed May 23, 2007 8:46 pm
            Re: question about symmertic evaluation Uri Blass Wed May 23, 2007 9:04 pm
            Re: question about symmertic evaluation Robert Hyatt Wed May 23, 2007 9:51 pm
                  Re: question about symmertic evaluation Uri Blass Wed May 23, 2007 10:04 pm
                  Re: question about symmertic evaluation Gerd Isenberg Wed May 23, 2007 10:09 pm
                        Re: question about symmertic evaluation Robert Hyatt Thu May 24, 2007 12:01 am
                              Re: question about symmertic evaluation Gerd Isenberg Thu May 24, 2007 7:37 am
                                    Re: question about symmertic evaluation H.G.Muller Thu May 24, 2007 8:06 am
                                          Re: question about symmertic evaluation Gerd Isenberg Thu May 24, 2007 9:24 am
                                                Re: question about symmertic evaluation H.G.Muller Thu May 24, 2007 10:39 am
                                                Re: question about symmertic evaluation Gerd Isenberg Thu May 24, 2007 11:36 am
                                                      Re: question about symmertic evaluation H.G.Muller Thu May 24, 2007 11:55 am
                                                Re: question about symmertic evaluation Gerd Isenberg Thu May 24, 2007 7:46 pm
                                          Re: question about symmertic evaluation Robert Hyatt Thu May 24, 2007 8:18 pm
                                                Re: question about symmertic evaluation Gerd Isenberg Thu May 24, 2007 8:55 pm
                                                      Re: question about symmertic evaluation Uri Blass Fri May 25, 2007 10:44 am
                                                            Re: question about symmertic evaluation Gerd Isenberg Fri May 25, 2007 6:28 pm
                                                                  Re: question about symmertic evaluation Uri Blass Fri May 25, 2007 7:42 pm
                                                                        Re: question about symmertic evaluation Gerd Isenberg Fri May 25, 2007 8:00 pm
                                    Re: question about symmertic evaluation Robert Hyatt Thu May 24, 2007 8:13 pm
                                          Re: question about symmertic evaluation Gerd Isenberg Thu May 24, 2007 8:33 pm
                                                Re: question about symmertic evaluation Robert Hyatt Sat May 26, 2007 1:05 am
                                                      Re: question about symmertic evaluation Gerd Isenberg Sat May 26, 2007 7:18 am
                                                            Re: question about symmertic evaluation Robert Hyatt Sat May 26, 2007 5:08 pm
                                                                  Re: question about symmertic evaluation Robert Hyatt Sat May 26, 2007 5:25 pm
                                                                  Re: question about symmertic evaluation Gerd Isenberg Sat May 26, 2007 6:23 pm
                                                                        Re: question about symmertic evaluation Robert Hyatt Sun May 27, 2007 2:48 pm
                  Re: question about symmertic evaluation Steven Edwards Thu May 24, 2007 3:42 am
                        Re: question about symmertic evaluation Robert Hyatt Thu May 24, 2007 8:20 pm
      Re: question about symmertic evaluation Robert Hyatt Wed May 23, 2007 9:50 pm
      Re: question about symmertic evaluation William H. Rogers Fri May 25, 2007 7:48 pm
            Re: question about symmertic evaluation Uri Blass Sat May 26, 2007 11:38 am
                  Re: question about symmertic evaluation H.G.Muller Sat May 26, 2007 2:07 pm
      Re: question about symmertic evaluation Vincent Diepeveen Sat May 26, 2007 7:27 pm
            Re: question about symmertic evaluation Gerd Isenberg Sat May 26, 2007 8:20 pm
            Re: question about symmertic evaluation Uri Blass Sat May 26, 2007 9:29 pm
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