Hello,


I have an expression that I have to minimize. The expression is a sum of piecewise functions each function depending on 3 variables.


Let's say **Si**(ai,bi,ci) is my function, i goes from 1 to N. The sum that I try to minimize is The sum of all **Si** functions (i from 1 to N).


Is the first derivative an option in this case? We're talking about 3\*N variables (ai,bi,ci where i is from 1 to N).


Thanks,


Iulian



Minimizing a sum of functions
Unless your functions have a very special structure (convex? independent as in @Gerhard's comment? smooth?) I (a) don't see how you can differentiate [you say your functions are piecewise], and (b) don't see what good it would do you if you could (you *might* find some local minimum, if the gradient had some very simple form, but would not know it was a global minimum).


