Function svm_group_classes

ml/src/svm.cpp:2329–2397

label: label name, start: begin of each class, count: #data of classes, perm: indices to the original data perm, length l, must be allocated before calling this subroutine

// label: label name, start: begin of each class, count: #data of classes, perm: indices
// to the original data perm, length l, must be allocated before calling this subroutine
static void
svm_group_classes(const svm_problem* prob,
                  int* nr_class_ret,
                  int** label_ret,
                  int** start_ret,
                  int** count_ret,
                  int* perm)
{
  int l = prob->l;
  int max_nr_class = 16;
  int nr_class = 0;
  int* label = Malloc(int, max_nr_class);
  int* count = Malloc(int, max_nr_class);
  int* data_label = Malloc(int, l);

  for (int i = 0; i < l; i++) {
    int this_label = static_cast<int>(prob->y[i]);
    int j;

    for (j = 0; j < nr_class; j++) {
      if (this_label == label[j]) {
        ++count[j];
        break;
      }
    }

    data_label[i] = j;

    if (j == nr_class) {
      if (nr_class == max_nr_class) {
        max_nr_class *= 2;
        label = static_cast<int*>(realloc(label, max_nr_class * sizeof(int)));
        count = static_cast<int*>(realloc(count, max_nr_class * sizeof(int)));
      }

      label[nr_class] = this_label;

      count[nr_class] = 1;
      ++nr_class;
    }
  }

  int* start = Malloc(int, nr_class);

  start[0] = 0;

  for (int i = 1; i < nr_class; i++)
    start[i] = start[i - 1] + count[i - 1];

  for (int i = 0; i < l; i++) {
    perm[start[data_label[i]]] = i;
    ++start[data_label[i]];
  }

  start[0] = 0;

  for (int i = 1; i < nr_class; i++)
    start[i] = start[i - 1] + count[i - 1];