Author: Omid David Tabibi
Date: 13:46:28 11/21/02
Go up one level in this thread
On November 21, 2002 at 15:55:55, Uri Blass wrote: >On November 21, 2002 at 09:10:32, Omid David Tabibi wrote: > >>On November 21, 2002 at 07:18:11, Uri Blass wrote: >> >>>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. >>>>> >>>>>Uri >>>> >>>>should be seconds,results,position >>>>I type too fast. >>>> >>>>Uri >>> >>>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. >>> >>>Uri >> >>Did you use the exact implementation I described in Figure 3? >> >>BTW, you have to compare the algorithms at deeper searches. A fixed 10 ply depth >>will be fine. > >Some notes: > >I do not the exact implementation in figure 3. >Differences: > >1)I do not use null move pruning at depth=1 because I have other pruning and I >did not change it. >null move pruning is used by movei only when the depth is at least 2. > >2)I did use research so I have not varaible to tell me about fail high and after >fail high, I trust the result of normal search(verify=false) with depth >that is reduced by 1. > >3)I already tested it at 300 seconds per move(still without research) and I >expect to have results tommorow. > >I am going to compare it with results of my previous version(null move pruning >R=3) >I use also other pruning ideas that I did not change. > >Uri I'm afraid that all these differences might result in a totally different structure. I strongly recommend you to try my exact implemenation first.
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