Would you please help me

1 
cvx_begin   quiet       % sdp  gp
variable phi(1,L) complex
variable  t
minimize t

for  k=1:size(X,1)
  x_k(k,:)=X(k,:).*phi;
end
for m=1:Mt
    for i=1:n
        PF(i)=trace(a(:,i)*a(:,i)'*x_k(m,:)'*x_k(m,:));
    end
    PS=PS+PF;
end

for   i=1:n
    delta_psd(i)=PS(i)-psd(i);
end
sum_dpsd=sum(delta_psd(:));
sum_dpsd<=t;                             
cvx_end

Disciplined convex programming error:
Invalid quadratic form: must be a scalar.

出错 (第 82 行)
PF(i)=trace(a(:,i)*a(:,i)’*x_k(m,:)’*x_k(m,:));

2 
for m=1:Mt
    for i=1:n
        PF(i)=a(:,i)'*a(:,i)*x_k(m,:)*x_k(m,:)';
%           PF(i)=trace(a(:,i)*a(:,i)'*x_k(m,:)'*x_k(m,:));
    end
    PS=PS+PF;
end

change the line 82 another mistake

Unable to perform assignment because value of type ‘cvx’ is not convertible to ‘double’.

3

Use expression holders http://cvxr.com/cvx/doc/basics.html#assignment-and-expression-holders

Rearrange per cyclic permutation invariance of trace
PF(i) = square_pos(norm(x_k(m,:)*a(:,i)),'fro'))

Edit: removed extraneous ,2 which was a typo.

4

Thanks a lot.
New message is “wrong using cvx/square_pos, too many varibles。”
when use
PF(i)=square_pos(norm((x_k(m,:)*a(:,i)),‘fro’))
I don’t know what does 2 mean

5

Sorry. I just edited my previous post to correct the typo.

6

Thank you.

A new problem is the optimal result of variable ‘phi’ is 0

How to avoid this station?

7

(upload://anXTdzWxGbGqa3ekK0cwcFvhQ6l.png)捕获

8

I was able to help you reformulate to comply with CVX’s rules. But it’s your optimization problem and input data. So you should figure out what to do about it if you don’t like the solution.

1 Like
9

Hi, Mark, I’m sorry to trouble you again.

f=linspace(0,1,n);
a=exp(-1i2pi*(0:L-1)’*f);

alf=0.01;
cvx_solver mosek
cvx_begin quiet % sdp gp
variable phi(1,L) complex
variable r
expression x_k(Mt,L)
expression PS(1,n)
expression PF(1,n)
expression X2
variable t
minimize t

for k=1:size(X,1)
X1(k,:)=X(k,:).*phi;
end
for m=1:Mt
for i=1:n
% PF(i)=a(:,i)’*a(:,i)*x_k(m,:slight_smile:x_k(m,:)’-rPsd_d(i);
% PF(i)=abs(a(:,i)*a(:,i)’*x_k(m,:)'x_k(m,:))-rPsd_d(i);
PF(i)=square_pos(norm((X1(m,:slight_smile:a(:,i)),‘fro’))-rPsd_d(i);
end
PS=PS+PF;
end
%
for i=1:n
delta_psd(i)=PS(i)-Psd_d(i);
end
sum(delta_psd(:))<=t;

for m=1:Mt
X2(m)=X1(m, : ) R1( X1(m,:))’;
end

sum(X2)<=t;
cvx_end

R1 is a Hermitian Matrix.
the message is
Disciplined convex programming error:
Invalid quadratic form: product is complex.
X2(m)=X1(m, : )* R1*( X1(m,:))’;

10

The problem was solved

for m=1:Mt
X2(m)=quad_form(X1(m,:).’,R1);
end