Is there any cvx function to express a matrix as a constraint?

I have many constraints in my problem. one of them is A>=0 which A is a matrix that includes some of the variables of the problem. I wanted to see if is there a direct function to express this constraint in cvx or I have to use another equivalent form for this constraint?

A post was merged into an existing topic: Disciplined convex programming error: Matrix powers not permitted

A post was merged into an existing topic: How to express a semidefinite convex matrix as a constraint in cvx?