Author: Stuart Cracraft
Date: 07:57:10 08/08/04
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On August 08, 2004 at 04:35:54, Tord Romstad wrote: >On August 08, 2004 at 01:47:12, Stuart Cracraft wrote: > >>Now my new question is what features do you think would help in solving >>problems rapidly. Extensions? > >Yes. But be careful -- It is easy to introduce lots of extensions which makes >your engine very good at solving problems, but which greatly reduce the >playing strength in real games. You should always play some test matches >before you decide whether you want to keep some new extension in your >program. > >The most useful extensions for solving problems rapidly are: > >1. Checks. > >2. Single reply to checks. > >3. Mate threats. These can be detected statically, or by using the return >value of a null move search. Extend if the null move search returns >-MATE_VALUE+Ply+2. This sounds very neresting and I want to try it but have a question. Is ply your "depth" in the routine or the current iteration number? Also, what do you do if your MATE value varies based on depth found at? How does that affect the above. > >4. Attacking moves. If you evaluate all internal nodes (as I do), compare >the value of the king safety component of the evaluation function before >and after a move is made. If a move dramatically reduces the opponent's >king safety, you extend. This one is a lot farther off for me since all I use is material and positional pc/sq lookup presently. I will remember this one though for the future. > >In order to avoid search explosions, you may want to use fractional >extensions. I extend by a full ply only for checks. Yes I must. My problem is that having tries various extensions, none did well for me, but I should revisit them with fractional extensions and see if there is a better result. > >Tord
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