def Semidef(n, name=None):
 var = SemidefUpperTri(n, name)
 fill_mat = Constant(upper_tri_to_full(n))
 return cvxtypes.reshape()((fill_mat * var), n, n)

def Semidef ( n , name = None ) : var = SemidefUpperTri ( n , name ) fill_mat = Constant ( upper_tri_to_full ( n ) ) return cvxtypes . reshape ( ) ( ( fill_mat * var ) , n , n )
an expression representing a positive semidefinite matrix .