use of optimization constraint mask in matlab fmincon or similar

Hello, I know that fmincon uses expressions for describing constraints .

but i want my optimization function to use a value mask instead of expresson

how do i define fmincon so it will be as close as possible to some vector value.

IE my cost function will be as close as possible to some value mask

[Matt J]

If you already know what the value that your cost function is supposed to have, what is there to minimize?