Author: Uri Blass
Date: 16:57:54 11/21/02
Go up one level in this thread
On November 21, 2002 at 16:46:28, Omid David Tabibi wrote: >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. I am interested in the question if verification search can help movei to be better so I compare time to get the solution and try first minimal changes. 1)If the target is to have something that is clearly superior to R=2 then I believe that I already have it and not only because of R=3. It means that I do not expect to do movei significantly better by removing pruning. 2)I am going to try later the following changes: a)Replace depth>1 by (!verify||depth>1) b)Maybe some changes of my pruning rules to try to make a) productive c)Add research Uri
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