+
+///////////////////////////////////////////////////////////////////////////
+// This program is free software: you can redistribute it and/or modify //
+// it under the terms of the version 3 of the GNU General Public License //
+// as published by the Free Software Foundation. //
+// //
+// 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/>. //
+// //
+// Written by Francois Fleuret, (C) IDIAP //
+// Contact <francois.fleuret@idiap.ch> for comments & bug reports //
+///////////////////////////////////////////////////////////////////////////
+
+#ifndef LOSS_MACHINE_H
+#define LOSS_MACHINE_H
+
+#include "misc.h"
+#include "sample_set.h"
+
+class LossMachine {
+ int _loss_type;
+
+public:
+ LossMachine(int loss_type);
+
+ void get_loss_derivatives(SampleSet *samples,
+ scalar_t *responses,
+ scalar_t *derivatives);
+
+ scalar_t loss(SampleSet *samples, scalar_t *responses);
+
+ scalar_t optimal_weight(SampleSet *sample_set,
+ scalar_t *weak_learner_responses,
+ scalar_t *current_responses);
+
+ // This method returns in sample_nb_occurences[k] the number of time
+ // the example k was sampled, and in sample_responses[k] the
+ // consistent response so that the overall loss remains the same. If
+ // allow_duplicates is set to 1, all samples will have an identical
+ // response (i.e. weight), but some may have more than one
+ // occurence. On the contrary, if allow_duplicates is 0, samples
+ // will all have only one occurence (or zero) but the responses may
+ // vary to account for the multiple sampling.
+
+ void subsample(int nb, scalar_t *labels, scalar_t *responses,
+ int nb_to_sample, int *sample_nb_occurences, scalar_t *sample_responses,
+ int allow_duplicates);
+};
+
+#endif