ADD: kmeans algorithm

src/cluster.c

 #include "cluster.h"
+#include <stdbool.h>
 #include "vector.h"
 
 
@@ -43,26 +44,58 @@ void cluster_add_point_fpt(cluster_fpt_t* cluster, vector_fpt_t* point) {
 }
 
 
-void cluster_update_center_int(cluster_int_t* cluster) {
-	vector_destroy_int(cluster->center);
+bool cluster_update_center_int(cluster_int_t* cluster) {
+	// save old center
+	vector_int_t* old_center = cluster->center;
+	// create new center
 	list_points_node_int_t* node = cluster->points->head;
 	cluster->center = vector_create_int(node->point->dim);
+	// sum all values in center
 	while (node != NULL) {
 		vector_add_inplace_int(cluster->center, *(node->point));
 		node = node->next;
 	}
+	// divide by number of points
 	vector_div_inplace_int(cluster->center, (int_t) cluster->points->size);
+	// check whether center has changed
+	bool changed = false;
+	for (size_t p = 0; p < cluster->center->dim; ++p) {
+		if (cluster->center->data[p] != old_center->data[p]) {
+			changed = true;
+			break;
+		}
+	}
+	// destroy old center
+	vector_destroy_int(old_center);
+	// return true if center has changed
+	return changed;
 }
 
-void cluster_update_center_fpt(cluster_fpt_t* cluster) {
-	vector_destroy_fpt(cluster->center);
+bool cluster_update_center_fpt(cluster_fpt_t* cluster) {
+	// save old center
+	vector_fpt_t* old_center = cluster->center;
+	// create new center
 	list_points_node_fpt_t* node = cluster->points->head;
 	cluster->center = vector_create_fpt(node->point->dim);
+	// sum all values in center
 	while (node != NULL) {
 		vector_add_inplace_fpt(cluster->center, *(node->point));
 		node = node->next;
 	}
+	// divide by number of points
 	vector_div_inplace_fpt(cluster->center, (fpt_t) cluster->points->size);
+	// check whether center has changed
+	bool changed = false;
+	for (size_t p = 0; p < cluster->center->dim; ++p) {
+		if (cluster->center->data[p] != old_center->data[p]) {
+			changed = true;
+			break;
+		}
+	}
+	// destroy old center
+	vector_destroy_fpt(old_center);
+	// return true if center has changed
+	return changed;
 }
 
 

src/cluster.h

 #ifndef PROG_KMEANS_CLUSTER_H
 #define PROG_KMEANS_CLUSTER_H
 
+#include <stdbool.h>
 #include <stdlib.h>
 #include "linkedlist.h"
 #include "vector.h"
@@ -32,9 +33,9 @@ void cluster_add_point_int(cluster_int_t* cluster, vector_int_t* point);
 void cluster_add_point_fpt(cluster_fpt_t* cluster, vector_fpt_t* point);
 
 
-void cluster_update_center_int(cluster_int_t* cluster);
+bool cluster_update_center_int(cluster_int_t* cluster);
 
-void cluster_update_center_fpt(cluster_fpt_t* cluster);
+bool cluster_update_center_fpt(cluster_fpt_t* cluster);
 
 
 void cluster_reset_int(cluster_int_t* cluster);

src/kmeans.c

@@ -90,18 +90,60 @@ cluster_fpt_t** kmeans_init_clusters_fpt(const vector_fpt_t** points, const size
 }
 
 
-void kmeans_int(vector_int_t** points, const size_t point_count, cluster_int_t** clusters, const size_t nb_clusters, fpt_t (* distance_function)(const vector_int_t*, const vector_int_t*)) {
-	//TODO
+void kmeans_int(vector_int_t** points, const size_t point_count, cluster_int_t** clusters, const size_t nb_clusters,
+				fpt_t (* distance_function)(const vector_int_t*, const vector_int_t*)) {
 	bool changed = true;
 	while (changed) {
 		changed = false;
+		for (size_t i = 0; i < point_count; ++i) {
+			vector_int_t* point = points[i];
+			// find closest cluster and add point to it
+			cluster_int_t* cmin = clusters[0];
+			int_t dmin = distance_function(point, cmin->center);
+			for (size_t k = 1; k < nb_clusters; ++k) {
+				cluster_int_t* current_cluster = clusters[k];
+				fpt_t dist = distance_function(point, current_cluster->center);
+				if (dist < dmin) {
+					cmin = current_cluster;
+					dmin = dist;
+				}
+			}
+			cluster_add_point_int(cmin, point);
+			// update all cluster centers
+			for (size_t k = 0; k < nb_clusters; ++k) {
+				if (cluster_update_center_int(clusters[k])) {
+					changed = true;
+				}
+			}
+		}
 	}
 }
 
-void kmeans_fpt(vector_fpt_t** points, const size_t point_count, cluster_fpt_t** clusters, const size_t nb_clusters, fpt_t (* distance_function)(const vector_fpt_t*, const vector_fpt_t*)) {
-	//TODO
+void kmeans_fpt(vector_fpt_t** points, const size_t point_count, cluster_fpt_t** clusters, const size_t nb_clusters,
+				fpt_t (* distance_function)(const vector_fpt_t*, const vector_fpt_t*)) {
 	bool changed = true;
 	while (changed) {
 		changed = false;
+		for (size_t i = 0; i < point_count; ++i) {
+			vector_fpt_t* point = points[i];
+			// find closest cluster and add point to it
+			cluster_fpt_t* cmin = clusters[0];
+			fpt_t dmin = distance_function(point, cmin->center);
+			for (size_t k = 1; k < nb_clusters; ++k) {
+				cluster_fpt_t* current_cluster = clusters[k];
+				fpt_t dist = distance_function(point, current_cluster->center);
+				if (dist < dmin) {
+					cmin = current_cluster;
+					dmin = dist;
+				}
+			}
+			cluster_add_point_fpt(cmin, point);
+			// update all cluster centers
+			for (size_t k = 0; k < nb_clusters; ++k) {
+				if (cluster_update_center_fpt(clusters[k])) {
+					changed = true;
+				}
+			}
+		}
 	}
 }