Error using .* (line 173) Disciplined convex programming error: Cannot perform the operation: {real affine} .* {convex}

[Mark_L_Stone]

You have violated CVX’s rules. Why isn't CVX accepting my model? READ THIS FIRST!

a/(1-a) is a linear fractional form.

See section 4.3.2 “Linear-fractional programming” of https://web.stanford.edu/~boyd/cvxbook/bv_cvxbook.pdf .for how to handle it.

Perhaps you can multiply both sides of the constraint by a to make that into a linear (affine) constraint.