Harm, I think of a more simple formula, because it seems to be easier to
find out an approximation than to weight a lot of parameters facing a lot
of other unhanded strange effects. Therefore my less dimensional approach
is looking like: f(s := sum of unbalanced big pieces' values, n :=
number of unbalanced big pieces, v := value of biggest opponents' piece).
So I intend to calculate the presumed value reduction e.g. as:
(s - v*n)/constant
P.S.: maybe it will make sense to down limit v by s/(2*n) to prevent a too big reduction, e.g. when no big opponents' piece would be present at all.
P.P.S.: There have been some more thoughts of mine on this question. Let w := sum of n biggest opponent pieces, limited by s/2. Then the formula should be:
(s - w)/constant
P.P.P.S.: My experiments suggest, that the constant is about 2.0
P^4.S.: I have implemented this 'Elephantiasis-Reduction' (as I will name it) in a new private SMIRF version and it is working well. My constant is currently 8/5. I found out, that it is good to calculate one more piece than being without value compensation, because that bottom piece pair could be of switched size and thus would reduce the reduction. Non existing opponent pieces will be replaced by a Knight piece value within the calculation. I noticed a speeding up of SMIRF when searching for mating combinations (by normal play). I also noticed that SMIRF is making sacrifices, incorporating vanishing such penalties of the introduced kind.
