--- /dev/null
+## Copyright (C) 2003,2004,2005 Michael Creel <michael.creel@uab.es>
+##
+## This program is free software; you can redistribute it and/or modify
+## it under the terms of the GNU General Public License as published by
+## the Free Software Foundation; either version 2 of the License, or
+## (at your option) any later version.
+##
+## This program is distributed in the hope that it will be useful,
+## but WITHOUT ANY WARRANTY; without even the implied warranty of
+## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+## GNU General Public License for more details.
+##
+## You should have received a copy of the GNU General Public License
+## along with this program; If not, see <http://www.gnu.org/licenses/>.
+
+## usage: [V,scorecontribs,J_inv] =
+## mle_variance(theta, data, model, modelargs)
+##
+## This is for internal use by mle_results
+
+# sandwich form of var-cov matrix
+function [V, scorecontribs, J_inv] = mle_variance(theta, data, model, modelargs)
+ scorecontribs = numgradient(model, {theta, data, modelargs});
+ n = rows(scorecontribs);
+ I = scorecontribs'*scorecontribs / n;
+ J = numhessian("mle_obj", {theta, data, model, modelargs});
+ J_inv = inverse(J);
+ V = J_inv*I*J_inv/n;
+endfunction