added example/test for fitting sigmoid on binary labels

shogun-toolbox · Aug 14, 2012 · d75793a · d75793a
1 parent 47bbe6a
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diff --git a/examples/undocumented/libshogun/Makefile b/examples/undocumented/libshogun/Makefile
@@ -54,6 +54,7 @@ TARGETS = basic_minimal \
 		  features_copy_subset_string_features \
 		  features_copy_subset_sparse_features \
 		  features_create_merged_copy \
+		  labels_binary_fit_sigmoid \
 		  mathematics_confidence_intervals \
 		  clustering_kmeans base_parameter_map \
 		  base_load_file_parameters \

diff --git a/examples/undocumented/libshogun/labels_binary_fit_sigmoid.cpp b/examples/undocumented/libshogun/labels_binary_fit_sigmoid.cpp
@@ -0,0 +1,43 @@
+/*
+ * 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 3 of the License, or
+ * (at your option) any later version.
+ *
+ * Written (W) 2012 Heiko Strathmann
+ */
+#include <shogun/labels/BinaryLabels.h>
+
+using namespace shogun;
+
+void test_sigmoid_fitting()
+{
+	CBinaryLabels* labels=new CBinaryLabels(10);
+	labels->set_confidences(SGVector<float64_t>(labels->get_num_labels()));
+
+	for (index_t i=0; i<labels->get_num_labels(); ++i)
+		labels->set_confidence(i%2==0 ? 1 : -1, i);
+
+	labels->get_confidences().display_vector("scores");
+	labels->scores_to_probabilities();
+
+	/* only two probabilities will be the result, repeatedly,
+	 * assert against reference implementation */
+	ASSERT(CMath::abs(labels->get_confidence(0)-0.8571428439385661)<10E-15);
+	ASSERT(CMath::abs(labels->get_confidence(1)-0.14285715606143384)<10E-15);
+
+	SG_UNREF(labels);
+}
+
+int main()
+{
+	init_shogun_with_defaults();
+
+//	sg_io->set_loglevel(MSG_DEBUG);
+
+	test_sigmoid_fitting();
+
+	exit_shogun();
+	return 0;
+}
+