Casadi Jacobian

casadi.py

class Fun(Callback):
        # sin(x+3*y)

        def __init__(self):
          Callback.__init__(self)
          self.construct("Fun", {})
        def get_n_in(self): return 2
        def get_n_out(self): return 1

        def eval(self,arg):
          x = arg[0]
          y = arg[1]
          z0 = 3*y
          z1 = x+z0
          z2 = sin(z1)
          return [z2]

        def has_forward(self,nfwd): return False
        def has_reverse(self,nadj): return False

        def has_jacobian(self): return True

        def get_jacobian(self, name, inames, onames, opts):
          x = SX.sym("x")
          y = SX.sym("y")
          out_g = SX.sym('out_g', Sparsity(1,1))
          J = Function(name, [x,y,out_g],[horzcat(cos(x+3*y),3*cos(x+3*y))], inames, onames, opts)
          return J