Author: Robert Hyatt
Date: 18:50:58 09/18/98
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On September 18, 1998 at 16:38:53, John Coffey wrote: >When a computer (such as crafty) lists the number of nodes that it has looked >at, does the number represent all the variations in the tree examines or does >it represent only the leaf positions evaluated? > I can't speak for others, but for me, it represents the number of chess positions searched. Positions are interior nodes, leaf nodes, and q-search nodes. Basically every time I make a move on the game board, that produces a new node... >On a 200mhz computer, Fritz5 claims to examine 200,000 positions per second, and >Crafty only about 80,000 per second. Yesterday I was only getting about 50,000 >positions per second out of Crafty on a 400 mhz PII, so I wonder how >much Windows 95 drags down the search? Could this be a reason why some chess >programs still use DOS? that is too low for crafty... it should hit a floor of 50-55K nodes per second on a 200 megahertz P6/200, which is about 1/2 the speed of your PII/400. It sounds like maybe you somehow had two crafties running, which can happen with winboard and win95... > >Even if we accept the Fritz numbers, we are still talking about a thousand >clock cycles per "node." Offhand that seems like a lot. If someone were >to write an engine that was strictly tactical (like a mate search), I wonder how >many clock cycles it would need per node? It makes me wonder if chess >algorithms could not be optimized somewhat? (I am not saying that they can >be optimized, just that I am wondering about it.) > 1000 is on the low edge of reality... 3000-5000 is on the upper end, although a program can be arbitrarily slow depending on what it does in evaluation. Crafty does full endpoint evaluation, spending almost exactly 1/2 of its time in the Evaluate() procedure... Fritz is obviously far lower than that, plus it is written in assembly... >Best wishes, > >John Coffey
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