how to find argmin to this vector

c=argmin f(a,b).where both a,b are M*1 and N*1 column matrices respectively.

How to get a,b for minimum value of f(a,b) from matlab

[James Tursa]

What does it mean to find the minimum value or index of two vectors with different lengths? Can you provide a short example of inputs and desired output?

[Murali Krishna AG]

Eg: Let function f=A^2+B^2+A*B+2*A^2*B

where A,B are known column matrices

Input:A,B

Expect output A,B.

I want to find in which A,B matrices the functiuon f could be minimum

Answer 1

[KSSV]

Are you looking for something like this?

Let a,b be your column matrices.

[a,b] = meshgrid(a,b) ;  % make them a matrix 
F = f(a,b) ;  % evaluate your function, use element by element operations in f 
[val,idx] = min(F(:)) ; 
amin = a(idx) ; 
bmin = b(idx) ; 

Have a look on fmincon.