Changed calc_neg_log_likelihood_and_neg_gradient to take the list of constrained parameter positions in to account. This allows the functionality to immediately be applied to the various models and estimations that are gradient based.
Changed calc_neg_log_likelihood_and_neg_gradient to take the list of constrained parameter positions in to account. This allows the functionality to immediately be applied to the various models and estimations that are gradient based.

timothyb0912/pylogit