pmlpp/mlpp/kmeans/kmeans.cpp

321 lines
7.9 KiB
C++

//
// KMeans.cpp
//
// Created by Marc Melikyan on 10/2/20.
//
#include "kmeans.h"
#include "../lin_alg/lin_alg.h"
#include "../utilities/utilities.h"
#include <climits>
#include <iostream>
#include <random>
Ref<MLPPMatrix> MLPPKMeans::get_input_set() {
return _input_set;
}
void MLPPKMeans::set_input_set(const Ref<MLPPMatrix> &val) {
_input_set = val;
_initialized = false;
}
int MLPPKMeans::get_k() {
return _k;
}
void MLPPKMeans::set_k(const int val) {
_k = val;
_initialized = false;
}
MLPPKMeans::MeanType MLPPKMeans::get_mean_type() {
return _mean_type;
}
void MLPPKMeans::set_mean_type(const MLPPKMeans::MeanType val) {
_mean_type = val;
_initialized = false;
}
void MLPPKMeans::initialize() {
if (_mean_type == MEAN_TYPE_KMEANSPP) {
_kmeanspp_initialization(_k);
} else {
_centroid_initialization(_k);
}
}
Ref<MLPPMatrix> MLPPKMeans::model_set_test(const Ref<MLPPMatrix> &X) {
return Ref<MLPPMatrix>();
}
Ref<MLPPVector> MLPPKMeans::model_test(const Ref<MLPPVector> &x) {
return Ref<MLPPVector>();
}
void MLPPKMeans::train(int epoch_num, bool UI) {
}
real_t MLPPKMeans::score() {
return 0;
}
Ref<MLPPVector> MLPPKMeans::silhouette_scores() {
return Ref<MLPPVector>();
}
MLPPKMeans::MLPPKMeans() {
_accuracy_threshold = 0;
_k = 0;
_initialized = false;
_mean_type = MEAN_TYPE_CENTROID;
}
MLPPKMeans::~MLPPKMeans() {
}
void MLPPKMeans::_evaluate() {
}
void MLPPKMeans::_compute_mu() {
}
void MLPPKMeans::_centroid_initialization(int k) {
}
void MLPPKMeans::_kmeanspp_initialization(int k) {
}
real_t MLPPKMeans::_cost() {
return 0;
}
void MLPPKMeans::_bind_methods() {
ClassDB::bind_method(D_METHOD("get_input_set"), &MLPPKMeans::get_input_set);
ClassDB::bind_method(D_METHOD("set_input_set", "value"), &MLPPKMeans::set_input_set);
ADD_PROPERTY(PropertyInfo(Variant::OBJECT, "input_set", PROPERTY_HINT_RESOURCE_TYPE, "MLPPMatrix"), "set_input_set", "get_input_set");
ClassDB::bind_method(D_METHOD("get_k"), &MLPPKMeans::get_k);
ClassDB::bind_method(D_METHOD("set_k", "value"), &MLPPKMeans::set_k);
ADD_PROPERTY(PropertyInfo(Variant::INT, "k"), "set_k", "get_k");
ClassDB::bind_method(D_METHOD("get_mean_type"), &MLPPKMeans::get_mean_type);
ClassDB::bind_method(D_METHOD("set_mean_type", "value"), &MLPPKMeans::set_mean_type);
ADD_PROPERTY(PropertyInfo(Variant::INT, "mean_type", PROPERTY_HINT_ENUM, "Centroid,KMeansPP"), "set_mean_type", "get_mean_type");
ClassDB::bind_method(D_METHOD("initialize"), &MLPPKMeans::initialize);
ClassDB::bind_method(D_METHOD("model_set_test", "X"), &MLPPKMeans::model_set_test);
ClassDB::bind_method(D_METHOD("model_test", "x"), &MLPPKMeans::model_test);
ClassDB::bind_method(D_METHOD("train", "epoch_num", "UI"), &MLPPKMeans::train, false);
ClassDB::bind_method(D_METHOD("score"), &MLPPKMeans::score);
ClassDB::bind_method(D_METHOD("silhouette_scores"), &MLPPKMeans::silhouette_scores);
BIND_ENUM_CONSTANT(MEAN_TYPE_CENTROID);
BIND_ENUM_CONSTANT(MEAN_TYPE_KMEANSPP);
}
/*
std::vector<std::vector<real_t>> MLPPKMeans::modelSetTest(std::vector<std::vector<real_t>> X) {
MLPPLinAlg alg;
std::vector<std::vector<real_t>> closestCentroids;
for (int i = 0; i < inputSet.size(); i++) {
std::vector<real_t> closestCentroid = mu[0];
for (int j = 0; j < r[0].size(); j++) {
bool isCentroidCloser = alg.euclideanDistance(X[i], mu[j]) < alg.euclideanDistance(X[i], closestCentroid);
if (isCentroidCloser) {
closestCentroid = mu[j];
}
}
closestCentroids.push_back(closestCentroid);
}
return closestCentroids;
}
std::vector<real_t> MLPPKMeans::modelTest(std::vector<real_t> x) {
MLPPLinAlg alg;
std::vector<real_t> closestCentroid = mu[0];
for (int j = 0; j < mu.size(); j++) {
if (alg.euclideanDistance(x, mu[j]) < alg.euclideanDistance(x, closestCentroid)) {
closestCentroid = mu[j];
}
}
return closestCentroid;
}
void MLPPKMeans::train(int epoch_num, bool UI) {
real_t cost_prev = 0;
int epoch = 1;
Evaluate();
while (true) {
// STEPS OF THE ALGORITHM
// 1. DETERMINE r_nk
// 2. DETERMINE J
// 3. DETERMINE mu_k
// STOP IF CONVERGED, ELSE REPEAT
cost_prev = Cost();
computeMu();
Evaluate();
// UI PORTION
if (UI) {
MLPPUtilities::CostInfo(epoch, cost_prev, Cost());
}
epoch++;
if (epoch > epoch_num) {
break;
}
}
}
real_t MLPPKMeans::score() {
return Cost();
}
std::vector<real_t> MLPPKMeans::silhouette_scores() {
MLPPLinAlg alg;
std::vector<std::vector<real_t>> closestCentroids = modelSetTest(inputSet);
std::vector<real_t> silhouette_scores;
for (int i = 0; i < inputSet.size(); i++) {
// COMPUTING a[i]
real_t a = 0;
for (int j = 0; j < inputSet.size(); j++) {
if (i != j && r[i] == r[j]) {
a += alg.euclideanDistance(inputSet[i], inputSet[j]);
}
}
// NORMALIZE a[i]
a /= closestCentroids[i].size() - 1;
// COMPUTING b[i]
real_t b = INT_MAX;
for (int j = 0; j < mu.size(); j++) {
if (closestCentroids[i] != mu[j]) {
real_t sum = 0;
for (int k = 0; k < inputSet.size(); k++) {
sum += alg.euclideanDistance(inputSet[i], inputSet[k]);
}
// NORMALIZE b[i]
real_t k_clusterSize = 0;
for (int k = 0; k < closestCentroids.size(); k++) {
if (closestCentroids[k] == mu[j]) {
k_clusterSize++;
}
}
if (sum / k_clusterSize < b) {
b = sum / k_clusterSize;
}
}
}
silhouette_scores.push_back((b - a) / fmax(a, b));
// Or the expanded version:
// if(a < b) {
// silhouette_scores.push_back(1 - a/b);
// }
// else if(a == b){
// silhouette_scores.push_back(0);
// }
// else{
// silhouette_scores.push_back(b/a - 1);
// }
}
return silhouette_scores;
}
// This simply computes r_nk
void MLPPKMeans::Evaluate() {
MLPPLinAlg alg;
r.resize(inputSet.size());
for (int i = 0; i < r.size(); i++) {
r[i].resize(k);
}
for (int i = 0; i < r.size(); i++) {
std::vector<real_t> closestCentroid = mu[0];
for (int j = 0; j < r[0].size(); j++) {
bool isCentroidCloser = alg.euclideanDistance(inputSet[i], mu[j]) < alg.euclideanDistance(inputSet[i], closestCentroid);
if (isCentroidCloser) {
closestCentroid = mu[j];
}
}
for (int j = 0; j < r[0].size(); j++) {
if (mu[j] == closestCentroid) {
r[i][j] = 1;
} else {
r[i][j] = 0;
}
}
}
}
// This simply computes or re-computes mu_k
void MLPPKMeans::computeMu() {
MLPPLinAlg alg;
for (int i = 0; i < mu.size(); i++) {
std::vector<real_t> num;
num.resize(r.size());
for (int i = 0; i < num.size(); i++) {
num[i] = 0;
}
real_t den = 0;
for (int j = 0; j < r.size(); j++) {
num = alg.addition(num, alg.scalarMultiply(r[j][i], inputSet[j]));
}
for (int j = 0; j < r.size(); j++) {
den += r[j][i];
}
mu[i] = alg.scalarMultiply(real_t(1) / real_t(den), num);
}
}
void MLPPKMeans::centroidInitialization(int k) {
mu.resize(k);
for (int i = 0; i < k; i++) {
std::random_device rd;
std::default_random_engine generator(rd());
std::uniform_int_distribution<int> distribution(0, int(inputSet.size() - 1));
mu[i].resize(inputSet.size());
mu[i] = inputSet[distribution(generator)];
}
}
void MLPPKMeans::kmeansppInitialization(int k) {
MLPPLinAlg alg;
std::random_device rd;
std::default_random_engine generator(rd());
std::uniform_int_distribution<int> distribution(0, int(inputSet.size() - 1));
mu.push_back(inputSet[distribution(generator)]);
for (int i = 0; i < k - 1; i++) {
std::vector<real_t> farthestCentroid;
for (int j = 0; j < inputSet.size(); j++) {
real_t max_dist = 0;
// SUM ALL THE SQUARED DISTANCES, CHOOSE THE ONE THAT'S FARTHEST
// AS TO SPREAD OUT THE CLUSTER CENTROIDS.
real_t sum = 0;
for (int k = 0; k < mu.size(); k++) {
sum += alg.euclideanDistance(inputSet[j], mu[k]);
}
if (sum * sum > max_dist) {
farthestCentroid = inputSet[j];
max_dist = sum * sum;
}
}
mu.push_back(farthestCentroid);
}
}
real_t MLPPKMeans::Cost() {
MLPPLinAlg alg;
real_t sum = 0;
for (int i = 0; i < r.size(); i++) {
for (int j = 0; j < r[0].size(); j++) {
sum += r[i][j] * alg.norm_sq(alg.subtraction(inputSet[i], mu[j]));
}
}
return sum;
}
*/