add functionality for counting SVs

1 files changed, 45 insertions, 0 deletions

diff --git a/src/msvmmaj_sv.c b/src/msvmmaj_sv.c
new file mode 100644
index 0000000..1358d4e
--- /dev/null
+++ b/src/msvmmaj_sv.c
@@ -0,0 +1,45 @@
+/**
+ * @file msvmmaj_sv.c
+ * @author Gertjan van den Burg
+ * @date May, 2014
+ * @brief Calculate the number of support vectors
+ *
+ * @details
+ * The function in this file can be used to calculate the number of support 
+ * vectors are left in a model.
+ *
+ */
+
+#include "msvmmaj.h"
+#include "msvmmaj_matrix.h"
+
+/**
+ * @brief Calculate the number of support vectors in a model
+ *
+ * @details
+ * If an object is correctly classified, the number of classes for which the 
+ * error q is larger than 1, is K-1 (i.e., there is no error w.r.t. any of the 
+ * other classes).  All objects for which this is not the case are thus support 
+ * vectors.
+ *
+ * @param[in] 	model 	MajModel with solution
+ * @param[in] 	data 	MajData to be used
+ * @return 		number of support vectors with this solution
+ *
+ */
+long msvmmaj_num_sv(struct MajModel *model, struct MajData *data)
+{
+	long i, j, num_correct, num_sv = 0;
+	double value;
+
+	for (i=0; i<data->n; i++) {
+		num_correct = 0;
+		for (j=0; j<data->K; j++) {
+			value = matrix_get(model->Q, data->K, i, j);
+			num_correct += (value > 1);
+		}
+		num_sv += (num_correct < data->K - 1);
+	}
+	
+	return num_sv;
+}