I have a model - function of two vectors $A$ and $B$. I have data that I want to fit to the model and find the model's parameters. The function needs to be convex to find the parameters using optimization; my question is: is the function convex?
The parameters are vectors $A$ and $B$ of $N$ elements. The data is an array $N\times N$. The function models element $M_{i,j}$ of the array as
$ M_{i,j} = c_1 {A_iA_j\over{\sum{A}}} + c_2{A_iB_j+c_3A_jB_i\over{\sum{B}}} $
And want to minimize
$ \sum|Data_{i,j}-M_{i,j}|^2 $