1 # Copyright (C) 2005 Michael Creel <michael.creel@uab.es>
3 # This program is free software; you can redistribute it and/or modify
4 # it under the terms of the GNU General Public License as published by
5 # the Free Software Foundation; either version 2 of the License, or
6 # (at your option) any later version.
8 # This program is distributed in the hope that it will be useful,
9 # but WITHOUT ANY WARRANTY; without even the implied warranty of
10 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11 # GNU General Public License for more details.
13 # You should have received a copy of the GNU General Public License
14 # along with this program; If not, see <http://www.gnu.org/licenses/>.
16 # Example likelihood function (Poisson for count data) with score
18 function [log_density, score] = poisson(theta, data, otherargs)
20 x = data(:,2:columns(data));
21 lambda = exp(x*theta);
22 log_density = -lambda + y .* (x*theta) - lgamma(y+1);
23 score = diag (y - lambda) * x;
24 if (otherargs{1} == 1) score = "na"; endif # provide analytic score or not?