Author: Christophe Theron
Date: 18:33:02 01/15/01
Go up one level in this thread
On January 15, 2001 at 18:24:23, Bas Hamstra wrote:
>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.
Unfortunately this has nothing to do with fractional extensions.
Christophe
> 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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