Author: Robert Hyatt
Date: 08:54:18 10/29/01
Go up one level in this thread
On October 29, 2001 at 10:43:35, Tony Werten wrote: >On October 29, 2001 at 10:29:26, Robert Hyatt wrote: > >>On October 29, 2001 at 04:05:08, Tony Werten wrote: >> >>>On October 28, 2001 at 21:06:11, Robert Hyatt wrote: >>> >>>>On October 28, 2001 at 18:20:43, Bas Hamstra wrote: >>>> >>>>>Again many bizar events. While discussing how boring and anti-positional Tiger >>>>>usually plays, with Jeroen Noomen, during the game Tao-CT, CT shot a h-pawn >>>>>through Tao's left eye. End of discussion. Well, let's call the thing an >>>>>idiot-savant, that's as far as I can go. Newcomer is EEC that does not use any >>>>>form of AlphaBeta at all. The author tried to explain the concept to me, but I'm >>>>>not sure I understand. Each move it plays a couple of shallow "matches" against >>>>>itsself and some kind of pattern matching is involved. Eventually that leads to >>>>>"votes" for different moves. The author says it has won some Blitz games against >>>>>GNU. >>>>> >>>>>Also new is "Gadget" from Hans Zijdenbos, written in Basic. Since it is brand >>>>>new, it has many things *not*. It has no hashtable, no pondering, no nullmove >>>>>and believe it or not, no quiescence search. Very little evaluation. Now can >>>>>that play chess? Amazingly, it does. Imagine Gadget searching 6-7 ply and Tao >>>>>12-13 ply, basically twice as deep. Yet it kept Tao negative for over twenty >>>>>moves, with sound play. Cock de Gorter said the same happened during >>>>>Crafty-Gadget. You would almost expect non nullmovers find positional holes in >>>>>the nullmove search or something. >>>>> >>>>>During a deep technical discussion with Johan de Koning whether to analyze mates >>>>>and countermates in the evaluation function or not, Jeroen Noomen drops by: >>>>>"aha, a rabbit". Apparently an enemy knight at h7, that can't move, is a rabbit. >>>>>We didn't get it, what do rabbits usually do? We could think of two things: a) >>>>>multiply and b) disappear in a hole. Since there were no minor promotions >>>>>possible in the foreseeable future and the rabbit finally disappeared in h7 I >>>>>wouldn't be surprised if b) has something to do with it. >>>>> >>>>>Well, Tao scored 3 out of 6 so far, on a PIII-500. Should have won against Ant, >>>>>which was positionally manoevred into a corner quite nicely, but alas, fell into >>>>>the "impotent pair" trap which I have no code for: bishop+unpromotable pawn, and >>>>>it became a draw. >>>>> >>>>>Finally: what's the matter with Crafty? It has the fastest hardware of all, but >>>>>seems to do relatively poorly, what's the matter? The new SE stuff, or what? >>>>> >>>>>TooTheLoo, >>>>>Bas. >>>> >>>>1. Does Crafty _really_ have the fastest hardware there? That's hard to >>>>believe with lots of 1.4 gig Dual AMD machines cheaply available. But in any >>>>case, it is possible. A dual 1.4 is faster than a quad-700 for Crafty, however, >>>>as the quad loses a bit more to overhead... >>> >>>Crafty doesn't have the fastest hardware but it's still quite fast. In the >>>endgame Crafty - XiniX I was outsearching Crafty several times by 3 to 5 ply on >>>a celeron 700 ! Unfortunately it wasn't enough to win, but it does seem to >>>indicate something is wrong in Crafty's endgame. XiniX had no problem searching >>>the same depth. >>> >>>Tony >>> >>>> >> >> >>I don't think the bug shows up like that. If there is a bug at all. Are you >>using the 3-4-5 piece EGTBs? That definitely affects the search speed. >>Otherwise, no ideas here... > >Yes. I probe 3-4-5 tables from disk in the search (not in quiescence ) XiniX was >not faster than Crafty in nps (but 4 times slower). In the positions the >branchingfactor is so small that 20 plies should not be a problem. > >Tony Can you post the position (or if you already have, indicate where) and I will look. One easy explanation is that if you see a score of (say) 3.00, while Crafty is saying 0.00, then the two programs are searching trees of vastly different 'shapes'. IE you can prune every 0.00 type branch while Crafty can't. This is often the reason for dramatically different search depths, when one program has an evaluation closer to the truth than the other. Or at least when one program has an evaluation that greatly enhances the pruning while the other has an evaluation that is forcing it to consider lots of lines that are not needed. > >> >> >> >>>>2. Crafty may well have a serious bug. Michel has reported that it will crash >>>>on a deep think, which is odd. There is no SE code in it, but it is possible >>>>that something in recent versions has left a bad array subscript or something. >>>>I am trying to get it to repeat a crash, but so far, nothing... >>>> >>>> y
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