evaluate the gradient of the objective function and the Jacobian of the constraints of a given AMPL problem
[g, jac] = ampl_evalg(asl, x)
the point where we evaluate the gradient and the Jacobian
a structure which handles the pointer to the problem
a vector which contains the value of the gradient (length: n_var)
a matrix which contains the value of the Jacobian (dimension: n_var x n_constr)
Evaluate the gradient of the objective function and the Jacobian of the constraintsof a given AMPL problem.