title: In pyomo how can one extract the second derivative from the objective function
body: <p>I'm working with pyomo and already have a model defined, with an objective function to go with it. After the model is solved, the objective function has certain parameters attached to it. So if i had a multi index variable <code>[x1, x2, x3]</code>, my quadratic objective function would suppose look something like this: <code>(x1^2 + 13*x2^2 + 10*x3^2) + (2*x1 +......)</code> . </p>
  
  <p>My question is: given that i can actually access this expression in string format from the objective, is there any way to obtain the second derivative of this function with respect to all the variables?</p>