Computer Chess Club Archives




Subject: Re: Position Evaluation

Author: Ratko V Tomic

Date: 20:04:18 11/22/99

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>I think that including initiative as an evaluation term is sufficient to
> provide this behavior.  The initiative term need not be too low.  A rule
> of thumb I learned once is that "90% of the time, the initiative is worth
> a pawn."
> Obviously, it would take some work to translate this into an eval function.
> Simply testing for initiative and adding 1 to a score would produce horrible
> results.  But the main idea is clear enough.

Easier said than done. Initiative, like beauty or elegance, is somewhat
intangible. It is a quality, not a quantity like material or mobility. Giving a
check with Bb5 or attacking a knight on g5 with h6 doesn't an initiative make,
even though initiative does often involve pushing the opponent's pieces back.

Additionally, initiative isn't free, one often has to unbalance the position,
even weaken some aspect of ones own position or give material. For something
that is hard to quantify (if possible at all)? Would a program playing without a
book, and with your hypothetical initiative term, come up with Evans gambit or
Kings gambit? (I know, some programs have hand-crafted instances they recognize
in which they will give an exchange or a piece for 1 or 2 pawns to get a strong
attack without seeing an explicit compensation within the horizon. But those
things, while working sometimes, more often hurt them than help. I think Hiarcs
7.32 has some of such hand-crafted logic and what some people here (including
myself) have noticed as occasional flakeness in Hiarcs' play, may be due to the
backfiring of this kind of evaluation override.)

>Quantifying the amount of initiative one or the other opponent has
>The frequent repetition of "static evaluation" ignores that dynamic terms can

Did something get mangled and chopped off at the end of your message? Of the
little that came through, it sounds interesting. Could you post the rest of it?

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