I need to use 'fminsearch' to optimize a parameter in determining critical damage Index. Kindly see Description for more

I have an Earthquake signal, decomposed into different frequency bands. For each band, there is a parameter that is a number which I need to optimize to minimise another value called Damage index which is a consequence of this Signal, and the parameter (when passed through a function). Damage Index isn't technically a function, as it has no dependent variables, its just a number as well, but becomes my Objective function.

Any suggestions?

[Ingrid]

your damage index is not just a number, you use some kind of function to calculate it so you can use this function in fminsearch

paramOptimize = fminsearch(@(x) functionCalculationDamageIndex(x),x0)

and then below define your calculation function

function damageIndex = functionCalculationDamageIndex(x)
% do your calculations here (calculate damage index based on the signal generated for the parameter x)