1 files changed, 85 insertions, 0 deletions
diff --git a/src/kernel.c b/src/kernel.c
new file mode 100644
index 0000000..ee64871
--- /dev/null
+++ b/src/kernel.c
@@ -0,0 +1,85 @@
+/**
+ * @file kernel.c
+ * @author Gertjan van den Burg (burg@ese.eur.nl)
+ * @date October 18, 2013
+ * @brief Defines main functions for use of kernels in MSVMMaj.
+ *
+ * @details
+ * Functions for constructing different kernels using user-supplied 
+ * parameters. Also contains the functions for decomposing the
+ * kernel matrix using several decomposition methods.
+ *
+ */
+#include <math.h>
+
+#include "kernel.h"
+
+void msvmmaj_make_kernel(struct MajModel *model, struct MajData *data)
+{
+	switch (model->kerneltype) {
+		case K_LINEAR:
+			break;
+		case K_POLY:
+			msvmmaj_make_kernel_poly(model, data);
+			break;
+		case K_RBF:
+			msvmmaj_make_kernel_rbf(model, data);
+			break;
+		case K_SIGMOID:
+			msvmmaj_make_kernel_sigmoid(model, data);
+			break;
+	}
+}
+
+void msvmmaj_make_kernel_rbf(struct MajModel *model, struct MajData *data)
+{
+	long i, j;
+	long n = model->n;
+	double value;
+	double *x1, *x2;
+	double *K = Calloc(double, n*(n+1));
+
+	for (i=0; i<n; i++) {
+		for (j=0; j<n; j++) {
+			x1 = &data->Z[i*(data->m+1)+1];
+			x2 = &data->Z[j*(data->m+1)+1];
+			value = msvmmaj_compute_rbf(x1, x2, model->kernelparam, n);
+			matrix_set(K, n+1, i, j+1, value);
+		}
+		matrix_set(K, n+1, i, 0, 1.0);
+	}
+
+	free(data->Z);
+	data->Z = K;
+	data->m = n;
+	model->m = n;
+}
+
+/**
+ * Implements k(x, z) = exp( -gamma * || x - z ||^2)
+ */
+double msvmmaj_compute_rbf(double *x1, double *x2, double *kernelparam, long n)
+{
+	long i;
+	double value = 0.0;
+
+	for (i=0; i<n; i++) 
+		value += (x1[i] - x2[i]) * (x1[i] - x2[i]);
+	value *= -kernelparam[0];
+	return exp(value);
+}
+
+/**
+ * Implements k(x, z) = (gamma * <x, z> + c)^degree
+ */
+double msvmmaj_compute_poly(double *x1, double *x2, double *kernelparam, long n)
+{
+	long i;
+	double value = 0.0;
+	for (i=0; i<n; i++)
+		value += x1[i]*x2[i];
+	value *= kernelparam[0];
+	value += kernelparam[1];
+	for (i=1; i<(int kernelparam[2]); i++)
+		value *= value;
+	:w