Author: Bas Hamstra
Date: 15:24:23 01/15/01
Go up one level in this thread
On January 14, 2001 at 10:18:08, Robert Hyatt wrote: >On January 14, 2001 at 00:37:12, Christophe Theron wrote: > >>On January 14, 2001 at 00:22:17, Robert Hyatt wrote: >> >>>On January 14, 2001 at 00:05:08, Christophe Theron wrote: >>> >>>>On January 13, 2001 at 17:19:19, Robert Hyatt wrote: >>>> >>>>>On January 13, 2001 at 17:13:13, Gian-Carlo Pascutto wrote: >>>>> >>>>>>Hi all, >>>>>> >>>>>>I just added code to my program to handle fractional extensions >>>>>>and recapture extensions. >>>>>> >>>>>>My problem now is: how do I test & tune these? I did what I >>>>>>normally do and ran it through WAC. It did worse. Probably not >>>>>>so surprising as they are nearly all rather simple tactical >>>>>>positions, so extending more (on checks...not so much on >>>>>>recaptures) is nearly always a win. >>>>>> >>>>>>Does anybody here have a testcase? Maybe a set of positions >>>>>>where it _really_ matters how you do your extensions? >>>>>> >>>>>>If you added frac. extensions you your program, what made you >>>>>>decide to do so? >>>>>> >>>>>>-- >>>>>>GCP >>>>> >>>>> >>>>>Do as I did. Make the extension amount something you can set via command. >>>>>Then run a potload of tests. I ran WAC with all the extensions set to >>>>>values between .5 and 1.0, in increments of .25. That is 3 cases for >>>>>each extension and I varied 4 different extensions. 81 tests and you then >>>>>look at which ones needed the fewest total nodes to solve _all_ the test >>>>>positions... >>>> >>>> >>>> >>>> >>>>So Crafty is cooked for WAC!? ;) >>>> >>>> >>>> >>>> Christophe >>> >>> >>>:) >>> >>>actually not, as I used a lot of other positions as well (IE I used some of >>>the "crafty goes deep" positions that were not tactical at all....) >> >> >> >>I am still using full ply extensions. >> >>I think I should try fractional extensions. Actually I did in the past. My 16 >>bits version used fractional extensions (in 1/100th of ply), but I was also >>doing much more extensions. I mean I had more reasons to do extensions. >> >>As for now, I prefer to be extremely "selective" in my extensions. There are a >>lot of conditions to meet before Tiger triggers an extension. >> >> >> >> Christophe > > >Fractional ply extensions give a chance for better control. IE you can say >"OK, I want to extend 3 checks, then not extend 1, then extend the next three, >but not the next... then you use a 3/4 ply extension... it is also useful >for controlling the one-legal-reply extension since that is really a double >extension on one ply and extending _two_ plies is potentially catastrophic. They can also be very powerful, see Genius. It sees amazing things in 0 sec. So it can be done. What about this, heavy extend near the root until 100.000 (or whatever) nodes are reached. Works brillantly. No choking. And then comes the deep search and the hashtable is full of nice things. Bas.
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