I get the error message:

??? Error using ==> cvx.norm at 52

Disciplined convex programming error:

Cannot perform the operation norm( {convex}, 1 )

Thank you.

Aliasing

I get the error message:

??? Error using ==> cvx.norm at 52

Disciplined convex programming error:

Cannot perform the operation norm( {convex}, 1 )

Thank you.

Aliasing

Just replace that outer norm with a sum. It is equivalent in this particular case.

Thank you for your definite answer. But another question:

I would say the simplest thing for you to do is try CVX 3.0 beta, which has modified the disciplined convex programming rules to accommodate situations like this. It can still be done in CVX 2.1, but some of the transformations must be done manually.

Thank you. Could you give me some advice on the concrete manual transformation using CVX2.1? The better is some references. Sorry for my elementary question.