Computer Chess Club Archives




Subject: Re: Doesn't appear to work for me (full data)

Author: Uri Blass

Date: 04:18:11 11/21/02

Go up one level in this thread

On November 21, 2002 at 06:26:16, Uri Blass wrote:

>On November 21, 2002 at 06:25:17, Uri Blass wrote:
>>On November 21, 2002 at 04:52:13, Omid David Tabibi wrote:
>>>On November 20, 2002 at 22:05:29, Robert Hyatt wrote:
>>>>On November 20, 2002 at 16:55:41, Gian-Carlo Pascutto wrote:
>>>>>Nullmove in Deep Sjeng uses an algorithm of my own, but I can
>>>>>switch it back to other systems easily. I did so for running
>>>>>a few tests.
>>>>>I made a version which uses Heinz Adaptive Nullmove Pruning
>>>>>and a version which uses your verification nullmove.
>>>>This would seem to be a bit harder than at first glance.  They say that
>>>>if the normal null-move search fails high, then do a D-1 regular search
>>>>to verify that, but while in that verification search, no further
>>>>verification searches are done, meaning that the normal null-move search
>>>>fail-high is treated just like we do it today..
>>>>I'm going to experiment with this myself, just for fun, but it seems that you
>>>>need to pass some sort of flag down thru the search calls indicating that
>>>>you are either below a verification-search node or not so that recursive
>>>>verification searches are not done...
>>>Exactly!! (finally someone read the article carefully)
>>>See Figure 3 for detailed implementation (the flag you mentioned which is passed
>>>down as a parameter for search(), is called 'verify' in the pseudo-code).
>>>At first stage leave alone the zugzwang detection part (the piece of code at the
>>>bottom of Figure 3). Due to instablilities, some programs might do a needless
>>>re-search. First let the algorithm work fine in general, and then do the
>>>zugwzang detection part.
>>I let the algorithm to work without zugwzang detection and first results seems
>>not to be good
>>Some positions I get at the same depth and
>>the only position so far in the gcp test suite that I got at smaller depth for
>>tactical reasons is
>>[D]5rk1/1r1qbnnp/R2p2p1/1p1Pp3/1Pp1P1N1/2P1B1NP/5QP1/5R1K w - - 0 1
>>I am going to try it in 10 sedconds per move and get resulkts in half an hour.
>should be seconds,results,position
>I type too fast.

Here are the results of the new version:

1     39     39
2      9     48
3      8     56
4     11     67
5      6     73
6      6     79
7      5     84
8      4     88
9      4     92
10      2     94

results of the old version seem better:

1     40     40
2     17     57
3      8     65
4      7     72
5      6     78
6      4     82
7      8     90
8      2     92
9      3     95
10      1     96

Remember also that I tested the olf version at more than 10 seconds per move so
if it changed it's mind after 20 seconds from the right move to the wrong move
the position is counted as a failure.


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Last modified: Thu, 07 Jul 11 08:48:38 -0700

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