Hi! everyone.

I’m new here today.

Kindly i need some help to solve my cvx optimization problem.

cvx_begin sdp

variable U1(n) complex

variable a1(1)

s1 = 0;

for i=1:length(theta)

s1_tmp = abs(-a1*Pd(i) + square_abs(U1’*vec(:,i)))

s1 = s1 + s1_tmp;

end

minimize(s1)

subject to

norm(U1,‘fro’) <= 1

a1 >= 0

cvx_end

When i run this code, i got the error code below:

Disciplined convex programming error:

Illegal operation: abs( {convex} ).

I guess s1_tmp = abs(-a1*Pd(i) + square_abs(U1’*vec(:,i))) term is not supported by cvx.

I prove that the objective function is convex since this is a function of absolute function.

Is there anything cvx expression to perform this?

Thank you for reading my question.