* fix MulticlassModel argmax, the loss must be included in training t…

…o find the MMV
shogun-toolbox · Aug 22, 2012 · 1a87bf0 · 1a87bf0
1 parent 50ba31c
commit 1a87bf0
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Showing 3 changed files with 27 additions and 4 deletions.
diff --git a/src/shogun/structure/MulticlassModel.cpp b/src/shogun/structure/MulticlassModel.cpp
@@ -81,11 +81,13 @@ CResultSet* CMulticlassModel::argmax(
 	// Find the class that gives the maximum score
 
 	float64_t score = 0, ypred = 0;
-	float64_t max_score = df->dense_dot(feat_idx, w.vector, feats_dim);
+	float64_t max_score = -CMath::INFTY;
 
 	for ( int32_t c = 1 ; c < m_num_classes ; ++c )
 	{
 		score = df->dense_dot(feat_idx, w.vector+c*feats_dim, feats_dim);
+		if ( training )
+			score += delta_loss(feat_idx, c);
 
 		if ( score > max_score )
 		{
@@ -119,7 +121,24 @@ float64_t CMulticlassModel::delta_loss(CStructuredData* y1, CStructuredData* y2)
 	ASSERT(rn1 != NULL);
 	ASSERT(rn2 != NULL);
 
-	return ( rn1->value == rn2->value ) ? 0 : 1;
+	return delta_loss(rn1->value, rn2->value);
+}
+
+float64_t CMulticlassModel::delta_loss(int32_t y1_idx, float64_t y2)
+{
+	REQUIRE(y1_idx >= 0 || y1_idx < m_labels->get_num_labels(),
+			"The label index must be inside [0, num_labels-1]\n");
+
+	CRealNumber* rn1 = CRealNumber::obtain_from_generic(m_labels->get_label(y1_idx));
+	float64_t ret = delta_loss(rn1->value, y2);
+	SG_UNREF(rn1);
+
+	return ret;
+}
+
+float64_t CMulticlassModel::delta_loss(float64_t y1, float64_t y2)
+{
+	return (y1 == y2) ? 0 : 1;
 }
 
 void CMulticlassModel::init_opt(

diff --git a/src/shogun/structure/MulticlassModel.h b/src/shogun/structure/MulticlassModel.h
@@ -133,6 +133,10 @@ class CMulticlassModel : public CStructuredModel
 	private:
 		void init();
 
+		/** Different flavours of the delta_loss that become handy */
+		float64_t delta_loss(float64_t y1, float64_t y2);
+		float64_t delta_loss(int32_t y1_idx, float64_t y2);
+
 	private:
 		/** number of classes */
 		int32_t m_num_classes;

diff --git a/src/shogun/structure/StructuredModel.cpp b/src/shogun/structure/StructuredModel.cpp
@@ -98,8 +98,8 @@ SGVector< float64_t > CStructuredModel::get_joint_feature_vector(
 
 float64_t CStructuredModel::delta_loss(int32_t ytrue_idx, CStructuredData* ypred)
 {
-	if ( ytrue_idx < 0 || ytrue_idx >= m_labels->get_num_labels() )
-		SG_ERROR("The label index must be inside [0, num_labels-1]\n");
+	REQUIRE(ytrue_idx >= 0 || ytrue_idx < m_labels->get_num_labels(),
+			"The label index must be inside [0, num_labels-1]\n");
 
 	CStructuredData* ytrue = m_labels->get_label(ytrue_idx);
 	float64_t ret = delta_loss(ytrue, ypred);