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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: Re: How to get futility pruning to work?    Posted: Wed Mar 07, 2012 11:40 pm Reply to topic Reply with quote
More careful measurements of time-to-depth (in many positions) showed only a pathetic 3-5% speedup by my pruning, not the 15-25% claimed earlier. Duh, no wonder I couldn't get any Elo advantage from pruning, whose primary purpose is to reduce ttd significantly.

I've written a new function IsMoveCheck(), which is 3x faster than making the move and then testing for check.

Don wrote:
You must never prune checks when doing futility (unless you really know what you are doing)
Thank you, that's very clear.

With these improvements, I now get a definite increase in playing strength due to futility pruning. Wahoo! It's not many Elo, but tuning the margins should help. Then it will be time to try late-move pruning as well.
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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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