Author: Christophe Theron
Date: 18:03:19 02/21/00
Go up one level in this thread
On February 21, 2000 at 16:52:03, Robert Hyatt wrote: >On February 21, 2000 at 13:33:58, Christophe Theron wrote: > >>On February 21, 2000 at 12:16:49, Tom Kerrigan wrote: >> >>>On February 21, 2000 at 11:37:52, Mark Taylor wrote: >>> >>>>An idea I had was to have a small incrmental value subtracted from the eval, >>>>this small increment getting larger the deeper into the tree search the eval was >>>>returned from. I had already done this for the values WON & LOST, but I >>> >>>This is a good idea. However, most chess programs have transposition tables. The >>>ideas are not compatible, because ttables assume that a position's score is >>>constant. You will probably want to have ttables instead of your penalty, >>>because once in a while there are huge benefits to having a ttable. >>> >>>>What I did in the end I made the first search iteration look at positional eval >>>>& material eval, then subsequent iterations looked at material eval only - but >>>>this was really a cop out. >>> >>>Yeah, I think this just confuses things. A long time ago I think there was a >>>program that ran on two CPUs. One CPU ran the regular evaluation function and >>>one was material-only. They checked each other. But programs these days get >>>along fine without material-only eval. >>> >>>-Tom >> >> >>The very old program Tech (I think the author was Gillogly, correct my spelling >>please, it was back in 1960) did this, but on only one processor I think. >> >>It played rather well, but was seriously handicaped by lack of deep positional >>understanding. >> >> >> Christophe > > >No. Tech was a 1970+ program. In the book "Echecs & Mips" written by Frédéric Louguet I have found: "1960: Creation of the Tech program, first program able to compute complicated tactical positions". I remember from articles written by David Levy that Tech used a deep tactical search (whetever deep meant at that time), but that positional evaluation was applied to the root moves only. I think this approach could be used by beginners in chess programming. The program could be surprisingly strong (compared to beginner's usual programs). Christophe > The program that did two searches was called >"Phoenix" by Jonathan Schaeffer. He ran a normal search with several >workstations in parallel, and a "minix" search using several more workstations >in parallel. Minix searched deeper looking only for tactical refutations of >the moves being considered by the normal search. > >Tech was a very fast, very "dumb" type technology approach, which is where >its name came from (tech). Jim occasionally posts on r.g.c.c and can be >reached there.
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