gathering variable values into matrix for further work

What I am working with is an MILP problem, with all inequality constraints. a matrix M(nxn), q(nx1). the problem is to maximize some function f, with constraints 0<=M*y-aq<=1-z where a is in R y(nx1) matrix variables, z (nx1) matrix of variables. I want to gather the resulting local variable values (like 2y1+3y2 ...) into a matrix Aineq. This is where I am struggling. I know i can set symbolic variables and do the resulting multiplications and but I want to collect those values into a matrix to for use in a function to solve the resulting MILP. There are other constraints but if I can solve the top problem all others are similar. I would like to stay away from symbolic values if possible as they chew up memory and really have no value to the imbedded function.

Any help would be greatly appreciated