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Subject: Re: search speed

Author: Dann Corbit

Date: 21:15:18 06/25/04

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On June 25, 2004 at 23:50:44, Robert Hyatt wrote:

>On June 25, 2004 at 22:19:41, Dann Corbit wrote:
>
>>On June 25, 2004 at 21:24:59, Robert Hyatt 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.
>>>>
>>>>Stuart
>>>
>>>
>>>another 50% or more.  Limit your q-search captures so you don't look at silly
>>>captures that obviously just lose material.
>>
>>How is that different from an alpha/beta search of captures only?
>
>
>Don't look at _all_ captures.  Only captures that appear to have a chance of
>producing something other than a fail-low (alpha cutoff)...

Do you determine the probability of a good capture with SEE?
Otherwise it seems you might miss obvious stuff like this:
[D]1r2k1r1/pbppnp1p/1b3P2/8/Q7/B1PB1q2/P4PPP/3R2K1 w - - bm Qxd7+;




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