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How to get futility pruning to work?
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Robert Purves



Joined: 15 Feb 2010
Posts: 155
Location: New Zealand
PostPost subject: How to get futility pruning to work?    Posted: Mon Mar 05, 2012 5:16 am Reply to topic Reply with quote
My (2600 Elo) engine distressingly fails to gain from futility pruning.
Code:
ev = NOT_EVALUATED;
for_each_move {
  if ( !pvNode && depth == 1 && !inCheck && move_is_not_the_first && move_is_quiet ) {
    if ( ev == NOT_EVALUATED ) ev = EvalForPrune();
    if ( ev + FUTILITY_MARGIN < alpha ) continue;
  }
  MakeMove();
  Search();
  ...
}

Numerous tests, with different values of FUTILITY_MARGIN, different meanings of move_is_quiet, and different implementations of EvalForPrune(), have gone nowhere.
I would be grateful for hints, tips or suggestions as to what may be wrong.

Robert P.
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Display posts from previous:   
Subject Author Date/Time
How to get futility pruning to work? Robert Purves Mon Mar 05, 2012 5:16 am
      Re: How to get futility pruning to work? Ferdinand Mosca Mon Mar 05, 2012 6:24 am
      Re: How to get futility pruning to work? Don Dailey Mon Mar 05, 2012 1:52 pm
            Re: How to get futility pruning to work? Robert Purves Mon Mar 05, 2012 10:16 pm
                  Re: How to get futility pruning to work? Don Dailey Mon Mar 05, 2012 10:42 pm
                        Re: How to get futility pruning to work? Robert Purves Wed Mar 07, 2012 11:40 pm
                              Re: How to get futility pruning to work? Ferdinand Mosca Thu Mar 08, 2012 4:30 am
                                    Re: How to get futility pruning to work? Robert Purves Thu Mar 08, 2012 8:55 am
                        Re: How to get futility pruning to work? Ferdinand Mosca Thu Mar 08, 2012 4:36 am
            Re: How to get futility pruning to work? Vincent Diepeveen Thu Mar 08, 2012 7:04 am
                  Re: How to get futility pruning to work? Robert Purves Sat Mar 10, 2012 12:38 am
                        Re: How to get futility pruning to work? Vincent Diepeveen Sun Mar 11, 2012 4:14 am
                              Re: How to get futility pruning to work? Vincent Diepeveen Sun Mar 11, 2012 4:41 am
                        Re: How to get futility pruning to work? Vincent Diepeveen Sun Mar 11, 2012 5:01 pm
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