Author: Omid David Tabibi
Date: 12:38:53 02/19/03
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On February 19, 2003 at 14:13:47, Uri Blass wrote: >On February 19, 2003 at 13:57:41, Dann Corbit wrote: > >>When you want to make your code faster, the most important thing is to find out >>where it is slow. I don't know how familiar you are with profiling, but a good >>profiler will show you a lot about your algorithms. On most programs, and >>certaintly for chess programs, most of the time will be dominated by a few hot >>spots. If you spend the effort on the hot spots, it will be enormously more >>beneficial than in other places. >> >>Nuts and bolts tweaky sorts of things are fun to learn. But an adjustment to >>the fundamental algorithm (if it is possible) is often dominatingly better than >>that. >> >>So, my steps to make something faster are like this: >>1. Profile to find the slow spots. >>2. Examine and understand the algorithms in the slow places >>3. Look for a better algorithm >>4. If a better algorithm exists, try it >>5. If a better algorithm does not exist, try to improve the existing algorithm >>6. If still a slow spot, resort to tweaky sorts of things and inline assembly. >> >>One idea that is often helpful is to precompute as much as possible, and store >>the results in a compact lookup table. Then the complex calculation becomes a >>simple lookup. > >I know it. > >The point is that the better algorithm that I have is to write similiar >functions to the functions that I have and when I write similiar functions I >also think of optimizing the previous functions. > >Today I have not a function to generate only captures and I need to do it but it >leads me to think again about my move generator and I find ideas that can do it >faster. > >I do not do the things that will help most to the speed of my program >because they may take time and I prefer first to see what I can improve >relatively fast. > >I also think that evaluation of endgames is more important but I like more doing >Movei faster because it is easier to test for bugs(if I get the same number of >nodes then I know that I probably have no bugs). But generating random numbers for hash key initializations might cause different hash-table overwrites, and thus the total node count might slightly vary on the same position and depth. > >Uri
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