Author: Vincent Diepeveen
Date: 17:52:53 06/05/01
Go up one level in this thread
On June 05, 2001 at 00:43:51, Dann Corbit wrote: >On June 04, 2001 at 14:33:45, Vincent Diepeveen wrote: > >>On June 04, 2001 at 07:14:42, Rudolf Huber wrote: >> >>>On June 04, 2001 at 04:35:19, Uri Blass wrote: >>> >>>>On June 04, 2001 at 03:36:25, Rudolf Huber wrote: >>>> >>>>> >>>>>A couple of days ago I said (in a discussion about mtd(f)) that my chess >>>>>program can search the starting position to 30 ply over night when the eval >>>>>evaluates material only: >>>>> >>>>> >>>>>SOS no eval >>>>> 1.00 0:00 0.00 1.h3 (2) >>>>> 2.00 0:00 0.00 1.h3 (45) >>>.... >>>>> 31.01 513:07 0.00 1.h3 h6 2.h4 h5 3.g3 g6 4.Rh3 Rh6 5.Rh1 Rh8 >>>>>(471.878.568) 573.3 >>>>> >>>>> >>>>>Actually 30 ply was reached after 2:41 hours. >>>>> >>>>>SW: no search extensions, normal nullmove pruning, normal quiescence >>>>> search >>>>>HW: 2xCeleron 466 MHz, 500 MByte Hash >>>>> >>>>> >>>>>Can anyone do better? >>>>Some questions: >>>> >>>>1)Is normal null move pruning recursive or not recursive null move pruning? >>>>In other words is it possible that your program will miss something that is 15 >>>>plies when it searches 30 plies not because of zunzwang. >>>> >>> >>>Recursive. >>> >>>Yes it is. But not likely. The position is not an endgame >>>and my zugzwang detection procedures were active. >>> >>>>2)What is the result without null move pruning? >>>>It will be interesting to compare your results with Deeper blue depthes in the >>>>positions from kasparov-deeper blue games. >>>> >>> >>>This 30 ply search works only in the starting position. In normal middlegame >>>positions it is lower. > >This is a very big puzzle to me then. Does your program really believe that 1. >h3 is the best move if you don't have an opening book? Of course SOS believes h3 is the best move by far. Within 30 plies you can't find a forced win of course that wins material! Imagine next search lines black proving whites play wrong. Let's assume quite some good play from black here and also writing besides it the depth needed for SOS h3 1 e5 2 null 3+R = 6 Bc5 7 null 8 Qf6 9 e3 10 Nh6 11 null 12+R = 15 So with just 2 pawn moves we can already come 15 ply EASILY!! Imagine how far we can get with 4 pawn moves + 1 rook move (Rh2) and some pawn swaps! 60 ply? Still no material win/loss is seen. Of course it's obvious for even the biggest beginner who is going to win or lose this. Note i had written a specialized version with just a move generator and a very stupid move ordering for white and just a few recaptures in qsearch. of course simple materialistic values only. no positional features... It got that 30 ply within a minute. Best regards, Vincent.
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