Remove all using directives for STL namespace and members

Made all STL usages explicit to be able automatically find all usages of
particular class or function.

modules/ml/src/em.cpp

@@ -99,7 +99,7 @@ bool EM::trainE(InputArray samples,
                 OutputArray probs)
 {
     Mat samplesMat = samples.getMat();
-    vector<Mat> covs0;
+    std::vector<Mat> covs0;
     _covs0.getMatVector(covs0);
 
     Mat means0 = _means0.getMat(), weights0 = _weights0.getMat();
@@ -156,7 +156,7 @@ bool EM::isTrained() const
 static
 void checkTrainData(int startStep, const Mat& samples,
                     int nclusters, int covMatType, const Mat* probs, const Mat* means,
-                    const vector<Mat>* covs, const Mat* weights)
+                    const std::vector<Mat>* covs, const Mat* weights)
 {
     // Check samples.
     CV_Assert(!samples.empty());
@@ -244,7 +244,7 @@ void preprocessProbability(Mat& probs)
 void EM::setTrainData(int startStep, const Mat& samples,
                       const Mat* probs0,
                       const Mat* means0,
-                      const vector<Mat>* covs0,
+                      const std::vector<Mat>* covs0,
                       const Mat* weights0)
 {
     clear();

modules/ml/src/gbt.cpp

@@ -1,26 +1,13 @@
 
 #include "precomp.hpp"
-#include <string>
 #include <time.h>
 
-using namespace std;
-
 #define pCvSeq CvSeq*
 #define pCvDTreeNode CvDTreeNode*
 
 #define CV_CMP_FLOAT(a,b) ((a) < (b))
 static CV_IMPLEMENT_QSORT_EX( icvSortFloat, float, CV_CMP_FLOAT, float)
 
-//===========================================================================
-static string ToString(int i)
-{
-    stringstream tmp;
-    tmp << i;
-
-    return tmp.str();
-}
-
-
 //===========================================================================
 //----------------------------- CvGBTreesParams -----------------------------
 //===========================================================================
@@ -1143,8 +1130,7 @@ void CvGBTrees::write( CvFileStorage* fs, const char* name ) const
 
     for ( int j=0; j < class_count; ++j )
     {
-        s = "trees_";
-        s += ToString(j);
+        s = cv::format("trees_%d", j);
         cvStartWriteStruct( fs, s.c_str(), CV_NODE_SEQ );
 
         cvStartReadSeq( weak[j], &reader );
@@ -1197,8 +1183,7 @@ void CvGBTrees::read( CvFileStorage* fs, CvFileNode* node )
 
     for (int j=0; j<class_count; ++j)
     {
-        s = "trees_";
-        s += ToString(j);
+        s = cv::format("trees_%d", j);
 
         trees_fnode = cvGetFileNodeByName( fs, node, s.c_str() );
         if( !trees_fnode || !CV_NODE_IS_SEQ(trees_fnode->tag) )

modules/ml/src/tree.cpp

@@ -2181,7 +2181,7 @@ CvDTreeSplit* CvDTree::find_split_cat_class( CvDTreeNode* node, int vi, float in
 
     int base_size = m*(3 + mi)*sizeof(int) + (mi+1)*sizeof(double);
     if( m > 2 && mi > data->params.max_categories )
-        base_size += (m*min(data->params.max_categories, n) + mi)*sizeof(int);
+        base_size += (m*std::min(data->params.max_categories, n) + mi)*sizeof(int);
     else
         base_size += mi*sizeof(int*);
     cv::AutoBuffer<uchar> inn_buf(base_size);
@@ -3300,7 +3300,7 @@ void CvDTree::split_node_data( CvDTreeNode* node )
     data->free_node_data(node);
 }
 
-float CvDTree::calc_error( CvMLData* _data, int type, vector<float> *resp )
+float CvDTree::calc_error( CvMLData* _data, int type, std::vector<float> *resp )
 {
     float err = 0;
     const CvMat* values = _data->get_values();