variant _1_kMeans(std::vector<std::vector<double>> img, std::vector<std::vector<double>> old_centers_v, int K, double epsilon kMeans_DOWN__1_kMeans_decl) {
cv::Mat centers(cv::Scalar(0)), old_centers(old_centers_v);
cv::Mat data0(img);
bool isrow = data0.rows == 1 && data0.channels() > 1;
int N = !isrow ? data0.rows : data0.cols;
int dims = (!isrow ? data0.cols : 1) * data0.channels();
int type = data0.depth();
if (!(data0.dims <= 2 && type == CV_32F && K > 0 && N >= K)) {
error("Cannot perform K-means algorithm for this configuration" kMeans_DOWN__1_kMeans_error_use);
return;
}
cv::Mat data(N, dims, CV_32F, data0.ptr(), isrow ? dims * sizeof(float) : static_cast<size_t>(data0.step));
cv::Mat temp(1, dims, type);
std::vector<int> counters(K, 0);
const float* sample = data.ptr<float>(0);
double max_center_shift = 0;
for (int k = 0; k < K; ++k) {
if (counters[k] != 0)
continue;
int max_k = 0;
for (int k1 = 1; k1 < K; ++k1) {
if (counters[max_k] < counters[k1])
max_k = k1;
}
double max_dist = 0;
int farthest_i = -1;
float* new_center = centers.ptr<float>(k);
float* old_center = centers.ptr<float>(max_k);
float* _old_center = temp.ptr<float>();
float scale = 1.f/counters[max_k];
for (int j = 0; j < dims; ++j)
_old_center[j] = old_center[j]*scale;
for (int i = 0; i < N; ++i) {
sample = data.ptr<float>(i);
double dist = cv::normL2Sqr_(sample, _old_center, dims);
if (max_dist <= dist) {
max_dist = dist;
farthest_i = i;
}
}
counters[max_k]--;
counters[k]++;
sample = data.ptr<float>(farthest_i);
for (int j = 0; j < dims; ++j) {
old_center[j] -= sample[j];
new_center[j] += sample[j];
}
}
for (int k = 0; k < K; ++k) {
float* center = centers.ptr<float>(k);
if (counters[k] == 0) {
error("For some reason one of the clusters is empty" kMeans_DOWN__1_kMeans_error_use);
return;
}
float scale = 1.f/counters[k];
for (int j = 0; j < dims; ++j)
center[j] *= scale;
double dist = 0;
const float* old_center = old_centers.ptr<float>(k);
for (int j = 0; j < dims; ++j) {
double t = center[j] - old_center[j];
dist += t * t;
}
max_center_shift = std::max(max_center_shift, dist);
}
std::vector<std::vector<double>> _centers;
centers.copyTo(_centers);
if (max_center_shift <= epsilon) {
result(_centers kMeans_DOWN__1_kMeans_result_use);
} else {
_1_loop(img, _centers, K, epsilon kMeans_DOWN__1_kMeans_loop_use);
}
}
double cv::kmeans( InputArray _data, int K,
InputOutputArray _bestLabels,
TermCriteria criteria, int attempts,
int flags, OutputArray _centers )
{
const int SPP_TRIALS = 3;
Mat data0 = _data.getMat();
bool isrow = data0.rows == 1;
int N = isrow ? data0.cols : data0.rows;
int dims = (isrow ? 1 : data0.cols)*data0.channels();
int type = data0.depth();
attempts = std::max(attempts, 1);
CV_Assert( data0.dims <= 2 && type == CV_32F && K > 0 );
CV_Assert( N >= K );
Mat data(N, dims, CV_32F, data0.ptr(), isrow ? dims * sizeof(float) : static_cast<size_t>(data0.step));
_bestLabels.create(N, 1, CV_32S, -1, true);
Mat _labels, best_labels = _bestLabels.getMat();
if( flags & CV_KMEANS_USE_INITIAL_LABELS )
{
CV_Assert( (best_labels.cols == 1 || best_labels.rows == 1) &&
best_labels.cols*best_labels.rows == N &&
best_labels.type() == CV_32S &&
best_labels.isContinuous());
best_labels.copyTo(_labels);
}
else
{
if( !((best_labels.cols == 1 || best_labels.rows == 1) &&
best_labels.cols*best_labels.rows == N &&
best_labels.type() == CV_32S &&
best_labels.isContinuous()))
best_labels.create(N, 1, CV_32S);
_labels.create(best_labels.size(), best_labels.type());
}
int* labels = _labels.ptr<int>();
Mat centers(K, dims, type), old_centers(K, dims, type), temp(1, dims, type);
std::vector<int> counters(K);
std::vector<Vec2f> _box(dims);
Vec2f* box = &_box[0];
double best_compactness = DBL_MAX, compactness = 0;
RNG& rng = theRNG();
int a, iter, i, j, k;
if( criteria.type & TermCriteria::EPS )
criteria.epsilon = std::max(criteria.epsilon, 0.);
else
criteria.epsilon = FLT_EPSILON;
criteria.epsilon *= criteria.epsilon;
if( criteria.type & TermCriteria::COUNT )
criteria.maxCount = std::min(std::max(criteria.maxCount, 2), 100);
else
criteria.maxCount = 100;
if( K == 1 )
{
attempts = 1;
criteria.maxCount = 2;
}
const float* sample = data.ptr<float>(0);
for( j = 0; j < dims; j++ )
box[j] = Vec2f(sample[j], sample[j]);
for( i = 1; i < N; i++ )
{
sample = data.ptr<float>(i);
for( j = 0; j < dims; j++ )
{
float v = sample[j];
box[j][0] = std::min(box[j][0], v);
box[j][1] = std::max(box[j][1], v);
}
}
for( a = 0; a < attempts; a++ )
{
double max_center_shift = DBL_MAX;
for( iter = 0;; )
{
swap(centers, old_centers);
if( iter == 0 && (a > 0 || !(flags & KMEANS_USE_INITIAL_LABELS)) )
{
if( flags & KMEANS_PP_CENTERS )
generateCentersPP(data, centers, K, rng, SPP_TRIALS);
else
{
for( k = 0; k < K; k++ )
generateRandomCenter(_box, centers.ptr<float>(k), rng);
}
}
else
{
if( iter == 0 && a == 0 && (flags & KMEANS_USE_INITIAL_LABELS) )
{
for( i = 0; i < N; i++ )
CV_Assert( (unsigned)labels[i] < (unsigned)K );
}
// compute centers
centers = Scalar(0);
for( k = 0; k < K; k++ )
counters[k] = 0;
for( i = 0; i < N; i++ )
{
sample = data.ptr<float>(i);
k = labels[i];
float* center = centers.ptr<float>(k);
j=0;
#if CV_ENABLE_UNROLLED
for(; j <= dims - 4; j += 4 )
{
float t0 = center[j] + sample[j];
float t1 = center[j+1] + sample[j+1];
center[j] = t0;
center[j+1] = t1;
t0 = center[j+2] + sample[j+2];
t1 = center[j+3] + sample[j+3];
center[j+2] = t0;
center[j+3] = t1;
}
#endif
for( ; j < dims; j++ )
center[j] += sample[j];
counters[k]++;
}
if( iter > 0 )
max_center_shift = 0;
for( k = 0; k < K; k++ )
{
if( counters[k] != 0 )
continue;
// if some cluster appeared to be empty then:
// 1. find the biggest cluster
// 2. find the farthest from the center point in the biggest cluster
// 3. exclude the farthest point from the biggest cluster and form a new 1-point cluster.
int max_k = 0;
for( int k1 = 1; k1 < K; k1++ )
{
if( counters[max_k] < counters[k1] )
max_k = k1;
}
double max_dist = 0;
int farthest_i = -1;
float* new_center = centers.ptr<float>(k);
float* old_center = centers.ptr<float>(max_k);
float* _old_center = temp.ptr<float>(); // normalized
float scale = 1.f/counters[max_k];
for( j = 0; j < dims; j++ )
_old_center[j] = old_center[j]*scale;
for( i = 0; i < N; i++ )
{
if( labels[i] != max_k )
continue;
sample = data.ptr<float>(i);
double dist = normL2Sqr(sample, _old_center, dims);
if( max_dist <= dist )
{
max_dist = dist;
farthest_i = i;
}
}
counters[max_k]--;
counters[k]++;
labels[farthest_i] = k;
sample = data.ptr<float>(farthest_i);
for( j = 0; j < dims; j++ )
{
old_center[j] -= sample[j];
new_center[j] += sample[j];
}
}
for( k = 0; k < K; k++ )
{
float* center = centers.ptr<float>(k);
CV_Assert( counters[k] != 0 );
float scale = 1.f/counters[k];
for( j = 0; j < dims; j++ )
center[j] *= scale;
if( iter > 0 )
{
double dist = 0;
const float* old_center = old_centers.ptr<float>(k);
for( j = 0; j < dims; j++ )
{
double t = center[j] - old_center[j];
dist += t*t;
}
max_center_shift = std::max(max_center_shift, dist);
}
}
}
if( ++iter == MAX(criteria.maxCount, 2) || max_center_shift <= criteria.epsilon )
break;
// assign labels
Mat dists(1, N, CV_64F);
double* dist = dists.ptr<double>(0);
parallel_for_(Range(0, N),
KMeansDistanceComputer(dist, labels, data, centers));
compactness = 0;
for( i = 0; i < N; i++ )
{
compactness += dist[i];
}
}
if( compactness < best_compactness )
{
best_compactness = compactness;
if( _centers.needed() )
centers.copyTo(_centers);
_labels.copyTo(best_labels);
}
}
return best_compactness;
}
