Added get_binary_for_class method that presents multiclass labels as …

…binary subtask
shogun-toolbox · May 16, 2012 · 7e00d0e · 7e00d0e
1 parent 3db552b
commit 7e00d0e
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diff --git a/src/shogun/features/Labels.cpp b/src/shogun/features/Labels.cpp
@@ -255,3 +255,16 @@ void CLabels::remove_all_subsets()
 {
 	m_subset_stack->remove_all_subsets();
 }
+
+CLabels* CLabels::get_binary_for_class(int32_t i)
+{
+	SGVector<float64_t> binary_labels(get_num_labels());
+
+	for (int32_t k=0; binary_labels.vlen; k++)
+	{
+		int32_t label = get_int_label(i);
+		binary_labels[k] = label == i ? +1.0 : -1.0;
+	}
+
+	return new CLabels(binary_labels);
+}
diff --git a/src/shogun/features/Labels.h b/src/shogun/features/Labels.h
@@ -216,6 +216,13 @@ class CLabels : public CSGObject
 		 * Calls subset_changed_post() afterwards */
 		virtual void remove_all_subsets();
 
+		/** returns labels containing +1 at positions with ith class
+		 *  and -1 at other positions
+		 *  @param i index of class
+		 *  @return new binary labels
+		 */
+		CLabels* get_binary_for_class(int32_t i);
+
 	public:
 
 		/** label designates classify reject */