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futility pruining, razoring question
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Lucas Braesch



Joined: 31 May 2010
Posts: 1750
PostPost subject: Re: futility pruining, razoring question    Posted: Sat Apr 07, 2012 1:59 am Reply to topic Reply with quote
diep wrote:
mar wrote:
lucasart wrote:

You're right. As pointed out by Martin, I got fooled by the chess programming wiki Wink
I'm currently testing this alternative:
Code:
   if (UseRazoring && depth <= RazorDepth
      && !is_pv && !is_mate_score(beta) && !in_check)
   {
      if (current_eval + RazorMargin(depth) <= alpha) {
         const int score = qsearch(B, alpha, beta, 0, ply+1, is_pv, si+1);
         if (score + RazorMargin(depth) <= alpha)   //**
            return score;
      }
   }

I've just ran 1000 games in 6"+0.1", and it scored 52% against my previous code. Thanks for the tip!

Shouldn't that be

Code:
   if (UseRazoring && depth <= RazorDepth
      && !is_pv && !is_mate_score(beta) && !in_check)
   {
      if (current_eval + RazorMargin(depth) <= alpha) {
         const int score = qsearch(B, alpha-RazorMargin(depth), beta-RazorMargin(depth), 0, ply+1, is_pv, si+1);
         if (score <= alpha - RazorMargin(depth))   //**
            return score;
      }
   }


instead? Because if you use fail-hard score will never get below alpha. So I guess your patch simply disables razoring.


the code looks like a crappy form of razoring. Razoring on alpha you need a huge margin. I remember Ed Schroeder was using 10 pawns there in some code he posted a few years ago.

Try razoring on beta, then you can use just 1 pawn or 1.5 pawn or so as a margin.

What are you talking about ?
At non PV nodes, alpha == beta - 1
At PV nodes, I don't do razoring
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Subject Author Date/Time
futility pruining, razoring question Marco Belli Wed Apr 04, 2012 6:21 pm
      Re: futility pruining, razoring question Robert Hyatt Thu Apr 05, 2012 7:07 pm
            Re: futility pruining, razoring question Karlo Bala Jr. Thu Apr 05, 2012 7:59 pm
            Re: futility pruining, razoring question Vincent Diepeveen Thu Apr 05, 2012 11:47 pm
      Re: futility pruining, razoring question Lucas Braesch Fri Apr 06, 2012 3:34 am
      Re: futility pruining, razoring question Martin Sedlak Fri Apr 06, 2012 3:35 am
            Re: futility pruining, razoring question Martin Sedlak Fri Apr 06, 2012 4:10 am
      Re: futility pruining, razoring question Martin Sedlak Fri Apr 06, 2012 5:15 am
            Re: futility pruining, razoring question Marco Costalba Fri Apr 06, 2012 5:45 am
                  Re: futility pruining, razoring question Lucas Braesch Fri Apr 06, 2012 7:22 am
                        Re: futility pruining, razoring question Martin Sedlak Fri Apr 06, 2012 7:30 am
                              Re: futility pruining, razoring question Lucas Braesch Fri Apr 06, 2012 8:36 am
                                    Re: futility pruining, razoring question Marco Costalba Fri Apr 06, 2012 11:42 am
                                          Re: futility pruining, razoring question Lucas Braesch Fri Apr 06, 2012 1:21 pm
                                          Re: futility pruining, razoring question Ricardo Barreira Fri Apr 06, 2012 3:00 pm
                              Re: futility pruining, razoring question Vincent Diepeveen Fri Apr 06, 2012 5:21 pm
                                    Re: futility pruining, razoring question Lucas Braesch Sat Apr 07, 2012 1:59 am
                                          Re: futility pruining, razoring question Vincent Diepeveen Sat Apr 07, 2012 8:22 am
                                                Re: futility pruining, razoring question Marco Costalba Sat Apr 07, 2012 9:52 am
                                                Re: futility pruining, razoring question Vincent Diepeveen Sat Apr 07, 2012 1:53 pm
                                                      Re: futility pruining, razoring question Ed Schroder Sat Apr 07, 2012 3:46 pm
                                                            Re: futility pruining, razoring question Vincent Diepeveen Sat Apr 07, 2012 4:07 pm
                                                      Re: futility pruining, razoring question Lucas Braesch Sun Apr 08, 2012 3:08 am
                                                            Re: futility pruining, razoring question Vincent Diepeveen Sun Apr 08, 2012 10:12 am
                                                                  Re: futility pruining, razoring question Matthew R. Brades Sun Apr 08, 2012 11:18 am
                                                                        Re: futility pruining, razoring question Marco Belli Mon Apr 09, 2012 7:42 pm
                                                                              Re: futility pruining, razoring question Marco Belli Mon Apr 09, 2012 8:23 pm
                                                                              Re: futility pruining, razoring question Martin Sedlak Mon Apr 09, 2012 9:04 pm
                                                                                    Re: futility pruining, razoring question Marco Belli Mon Apr 09, 2012 9:24 pm
                                                                                          Re: futility pruining, razoring question Marco Belli Tue Apr 10, 2012 10:52 am
                                                                                          Re: futility pruining, razoring question Martin Sedlak Tue Apr 10, 2012 11:58 am
                        Re: futility pruining, razoring question John Merlino Sat Apr 07, 2012 5:10 pm
                              Re: futility pruining, razoring question Vincent Diepeveen Sat Apr 07, 2012 5:41 pm
                                    Re: futility pruining, razoring question John Merlino Sat Apr 07, 2012 5:54 pm
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