Author: Robert Hyatt
Date: 13:58:58 07/25/02
Go up one level in this thread
On July 25, 2002 at 14:06:39, Bas Hamstra wrote: >>>>IID is not a huge thing. It mainly helps where you fail high but can't get >>>>a real score so that the next iteration, you end up with no hash moves for >>>>the PV search... IID will supply good moves. >>> >>>All you get is a reasonable move from a D-2 search. Why not store the original >>>hashmove in stead? >> >>Where would you get it from? I use the fact that there is no hash move >>for a PV node to trigger the IID search... > >>>So when you normally store a UPPER score, in stead of saving >>>no move at all, you save the original hashmove? I don't see why IID would >>>provide a better move than that... >> >>Because at the _next_ ply in the tree, you have no move because it is a >>fail low position... > >I don't understand. In case of a fail-low position I store the *original* >hashmove which was a bestmove. So, I never am without hashmove. You _must_ be without one at times. How can you store the "original" best move is there is no hash entry there at all? I'll bet that if you count the number of times you call hash probe, and the number of times you don't get a "hit", the difference will be extremely high. And in _each_ of those misses, you don't get any kind of hash move at all. Which is where IID helps. > >>Also, you assume that you already have a hash entry with a best move. But >>that is not a certainty... So if you don't have one, you can't "save it" >>with your trick. IID is simply a solution for this that is trivial to >>implement.... > >Yes, that is correct, there is not always an original hashmove. In particular >the last few plies, where it is least important, this can be the case. I tried >both IID and this, and for the moment I like this better. > >Best regards, >Bas.
This page took 0 seconds to execute
Last modified: Thu, 15 Apr 21 08:11:13 -0700
Current Computer Chess Club Forums at Talkchess. This site by Sean Mintz.