void cluster_document::kmedoids(int clusters, std::vector<cluster_document> &document_list) {
int length = document_list.size();
std::vector<int> medoid_ids = random_subset(clusters, length);
recompute_clusters(medoid_ids, document_list);
int steps = KMEDOIDS_STEPS;
double cost = compute_cost(medoid_ids, document_list);
while (steps-- > 0) {
//std::cerr << steps << std::endl;
int best_document = -1;
double best_cost = cost;
for (auto &document: document_list) {
int old_medoid = medoid_ids[document.cluster_];
if (old_medoid == document.id_) {
continue;
}
medoid_ids[document.cluster_] = document.id_;
double new_cost = compute_cost(medoid_ids, document_list);
if (new_cost < best_cost) {
cost = best_cost = new_cost;
best_document = document.id_;
}
medoid_ids[document.cluster_] = old_medoid;
}
if (best_document == -1) {
break;
}
auto &document = document_list[best_document];
medoid_ids[document.cluster_] = document.id_;
recompute_clusters(medoid_ids, document_list);
}
}
void cluster_document::kmeans(int clusters, std::vector<cluster_document> &document_list) {
int length = document_list.size();
std::vector<int> centroid_ids = random_subset(clusters, length);
int steps = KMEANS_STEPS;
while (steps--) {
//std::cerr << "Steps left: " << steps << std::endl;
//reassigning
for (auto &document: document_list) {
document.cluster_ = 0;
for (int cluster = 0; cluster < clusters; ++cluster) {
int id = centroid_ids[cluster];
int old_id = centroid_ids[document.cluster_];
if (document.distance(id) < document.distance(old_id)) {
document.cluster_ = cluster;
}
}
}
//recomputing centroids
std::vector<double> cluster_distance(length);
for (int i = 0; i < length; ++i) {
for (int j = i + 1; j < length; ++j) {
if (document_list[i].cluster_ ==
document_list[j].cluster_) {
cluster_distance[i] += document_list[i].distance(j);
cluster_distance[j] += document_list[j].distance(i);
}
}
}
centroid_ids.assign(clusters, -1);
for (auto &document: document_list) {
if (centroid_ids[document.cluster_] == -1 ||
cluster_distance[centroid_ids[document.cluster_]] >
cluster_distance[document.id_]) {
centroid_ids[document.cluster_] = document.id_;
}
}
}
}
int main()
{
for (size_t n = 0; n <= 100; ++n)
{
for (size_t m = 0; m <= n; ++m)
{
std::vector< size_t > values;
for (size_t j = 0; j < n; ++j)
{
values.push_back(j);
}
for (int i = 0; i < 100; ++i)
{
std::vector< size_t > subset = random_subset(values,m);
assert(subset.size() == m);
std::vector< bool > values_seen(n, false);
/* make sure all values are valid and don't repeat */
for (const size_t x : subset)
{
assert(x < n);
assert(values_seen[x] == false);
values_seen[x] = true;
}
}
}
std::cout << "passed random tests for arrays of size " << n << std::endl;
}
return 0;
}
int main(int argc, char** argv)
{
int opt_char;
enum algorithm_t {
e_null = 0,
e_permutation = 1,
e_subset = 2,
};
algorithm_t algorithm = e_null;
/**
* long options is not portal using getopt, ignored.
*/
while ((opt_char = getopt(argc, argv, "hs:a:")) != -1) {
switch (opt_char) {
case 's':
{
int seed = strtol(optarg, 0, 10);
srand(seed);
break;
}
case 'a':
switch (*optarg) {
case 'p':
algorithm = e_permutation;
break;
case 's':
algorithm = e_subset;
break;
default:
fprintf(stderr, "unsupported algorithm %s\n", optarg);
exit(1);
}
break;
case 'h':
fprintf(stderr, "Usage: %s -s<SEED> integer-list\n", argv[0]);
exit(1);
case '?':
exit(1);
}
}
if (!algorithm) {
fprintf(stderr, "algorithm(-a) not specified\n");
exit(1);
}
switch(algorithm) {
case e_permutation:
{
int len = argc-optind;
int* a = new int[len];
for (int i = 0; i < len; ++i)
a[i] = strtol(argv[optind+i], 0, 10);
random_permutation(len, a);
for (int i = 0; i < len; ++i)
fprintf(stdout, "%d ", a[i]);
fprintf(stdout, "\n");
delete a;
break;
}
case e_subset:
{
int m = strtol(argv[optind], 0, 10);
int len = argc-optind-1;
int* b = new int[m];
int* a = new int[len];
for (int i = 0; i < len; ++i)
a[i] = strtol(argv[optind+1+i], 0, 10);
random_subset(len, a, m, b);
std::sort(b, b+m);
for (int i = 0; i < m; ++i)
fprintf(stdout, "%d ", b[i]);
fprintf(stdout, "\n");
delete a;
delete b;
break;
}
}
return 0;
}