Author: Dann Corbit
Date: 20:00:15 06/25/04
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On June 25, 2004 at 22:48:03, Uri Blass wrote: >On June 25, 2004 at 16:46:31, Dann Corbit wrote: > >>On June 25, 2004 at 16:36:19, Stuart Cracraft wrote: >> >>>Just a note that I got my hashing working in a >>>quick hack program I've put together for other >>>reasons and it was nasty even though I've been >>>through it over and over through the decades. >>>I empathize with other hashers who have felt or >>>are feeling hashed. >>> >>>It is well worth it. A typical 8 ply search early >>>in the game might reduce 50%+ in total nodes searched >>>and 50%+ in total time. >>> >>>These are dwarfed by null move's effect though in >>>the same positions (90% and 90%). >>> >>>So my question is, these are well-known methods to >>>substantially reduce the number of nodes and amount >>>of time for most searches -- I wonder if there is >>>anything else that is as large and as comparable >>>at these large 50%/90% types of reductions. >> >>What is your branching factor? >> >>The best programs have a branching factor between 2 and 3. >> >>If you already have a branching factor in that range, do not expect any more >>really dramatic speedups. > >2 mistakes: >1)it is possible to make the program worse by more pruning and a smaller >branching factor so you cannot use the branching factor to decide if it is >impossible to make dramtic speedup. If you have a big branching factor, then you can have a huge speedup without damaging the search. All the best programs have a branching factor less than 3.0. If your program has a branching factor larger than this, then you can make your program faster. Now, you can do stupid pruning and make it smaller and the program will not be better. So it is necessary but not sufficient for a condition. >2)I do not think that the best programs cannot expect more dramatic speedups in >the qsearch thanks to new ideas. More than null move or hashing? I doubt it.
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