This is often an indication that an equality constraint was written with one equals '=' instead of two '=='

1

Hello, everyone! Do you know what lead to the error?

Error:
      The following cvx variable(s) have been cleared or overwritten:
          V

      This is often an indication that an equality constraint was written with one 
      equals '=' instead of two '=='.  The model must be rewritten before cvx can 
      proceed.

CVX:     cvx_begin quiet
        cvx_solver MOSEK
      
        variable V(M,M*N) 

        subject to

        for n=1:N
            V(:,(n-1)*M+1:n*M) ==  hermitian_semidefinite(M);
        end
2

That code should not generate a CVX error message, and didn’t when I set some values for M and N` and ran it using CVX 2.2.

Perhaps you’re not showing us everything, or the error message you showed does not correspond to that code, or you are using CVX 3.0beta, or your MATLAB session was corrupted, or your CVX installation is screwed up.

Try running it in a new MATLAB session. Make sure you use CVX 2.2, not CVX 3.0beta, which is riddled with bugs.

3

Thank you for your reply. I find my other expression has an error.