kmeans()

kmeans_result kmeans

(

kmeans_config *

config

)

Definition at line 249 of file kmeans.c.

References kmeans_config::centers, kmeans_config::centroid_method, kmeans_config::clusters, kmeans_config::distance_method, kmeans_config::k, KMEANS_ERROR, KMEANS_EXCEEDED_MAX_ITERATIONS, kmeans_free, kmeans_malloc, KMEANS_MAX_ITERATIONS, KMEANS_OK, LW_ON_INTERRUPT, kmeans_config::max_iterations, kmeans_config::num_objs, kmeans_config::objs, kmeans_config::total_iterations, update_means(), and update_r().

Referenced by lwgeom_cluster_2d_kmeans().

{
        int iterations = 0;
        int *clusters_last;
        size_t clusters_sz = sizeof(int)*config->num_objs;

        assert(config);
        assert(config->objs);
        assert(config->num_objs);
        assert(config->distance_method);
        assert(config->centroid_method);
        assert(config->centers);
        assert(config->k);
        assert(config->clusters);
        assert(config->k <= config->num_objs);

        /* Zero out cluster numbers, just in case user forgets */
        memset(config->clusters, 0, clusters_sz);

        /* Set default max iterations if necessary */
        if (!config->max_iterations)
                config->max_iterations = KMEANS_MAX_ITERATIONS;

        /*
         * Previous cluster state array. At this time, r doesn't mean anything
         * but it's ok
         */
        clusters_last = kmeans_malloc(clusters_sz);

        while (1)
        {
                LW_ON_INTERRUPT(kmeans_free(clusters_last); return KMEANS_ERROR);

                /* Store the previous state of the clustering */
                memcpy(clusters_last, config->clusters, clusters_sz);

#ifdef KMEANS_THREADED
                update_r_threaded(config);
                update_means_threaded(config);
#else
                update_r(config);
                update_means(config);
#endif
                /*
                 * if all the cluster numbers are unchanged since last time,
                 * we are at a stable solution, so we can stop here
                 */
                if (memcmp(clusters_last, config->clusters, clusters_sz) == 0)
                {
                        kmeans_free(clusters_last);
                        config->total_iterations = iterations;
                        return KMEANS_OK;
                }

                if (iterations++ > config->max_iterations)
                {
                        kmeans_free(clusters_last);
                        config->total_iterations = iterations;
                        return KMEANS_EXCEEDED_MAX_ITERATIONS;
                }

        }

        kmeans_free(clusters_last);
        config->total_iterations = iterations;
        return KMEANS_ERROR;
}

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