From 35d53fa5fdc8018fca8af1cf8e02b5354cd7a1d2 Mon Sep 17 00:00:00 2001
From: Boris Stefanovic <owldev@bluewin.ch>
Date: Wed, 8 Jun 2022 10:57:26 +0200
Subject: [PATCH] ADD: kmeans algorithm
---
src/cluster.c | 41 +++++++++++++++++++++++++++++++++++++----
src/cluster.h | 5 +++--
src/kmeans.c | 50 ++++++++++++++++++++++++++++++++++++++++++++++----
3 files changed, 86 insertions(+), 10 deletions(-)
diff --git a/src/cluster.c b/src/cluster.c
index bfb7149..fbc62fb 100644
--- a/src/cluster.c
+++ b/src/cluster.c
@@ -1,4 +1,5 @@
#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;
}
diff --git a/src/cluster.h b/src/cluster.h
index 0e2993a..0888785 100644
--- a/src/cluster.h
+++ b/src/cluster.h
@@ -1,6 +1,7 @@
#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);
diff --git a/src/kmeans.c b/src/kmeans.c
index a8b6df1..1179541 100644
--- a/src/kmeans.c
+++ b/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;
+ }
+ }
+ }
}
}
--
GitLab