label_dictionary.cc

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#include "reductions.h"
#include "cost_sensitive.h"
#include "label_dictionary.h"

namespace LabelDict
{
constexpr size_t hash_lab(size_t lab) noexcept { return 328051 + 94389193 * lab; }

void del_example_namespace(example& ec, namespace_index ns, features& fs)
{
  // print_update is called after this del_example_namespace,
  // so we need to keep the ec.num_features correct,
  // so shared features are included in the reported number of "current features"
  // ec.num_features -= numf;
  features& del_target = ec.feature_space[(size_t)ns];
  assert(del_target.size() >= fs.size());
  assert(ec.indices.size() > 0);
  if (ec.indices.last() == ns && ec.feature_space[(size_t)ns].size() == fs.size())
    ec.indices.pop();
  ec.total_sum_feat_sq -= fs.sum_feat_sq;
  ec.num_features -= fs.size();
  del_target.truncate_to(del_target.size() - fs.size());
  del_target.sum_feat_sq -= fs.sum_feat_sq;
}

void add_example_namespace(example& ec, namespace_index ns, features& fs)
{
  bool has_ns = false;
  for (size_t i = 0; i < ec.indices.size(); i++)
    if (ec.indices[i] == (size_t)ns)
    {
      has_ns = true;
      break;
    }

  if (!has_ns)
    ec.indices.push_back((size_t)ns);

  bool audit = fs.space_names.size() > 0;
  features& add_fs = ec.feature_space[(size_t)ns];
  for (size_t i = 0; i < fs.size(); ++i)
  {
    add_fs.push_back(fs.values[i], fs.indicies[i]);
    if (audit)
      add_fs.space_names.push_back(fs.space_names[i]);
  }
  ec.total_sum_feat_sq += fs.sum_feat_sq;

  ec.num_features += fs.size();
}

void add_example_namespaces_from_example(example& target, example& source)
{
  for (namespace_index idx : source.indices)
  {
    if (idx == constant_namespace)
      continue;
    add_example_namespace(target, idx, source.feature_space[idx]);
  }
}

void del_example_namespaces_from_example(example& target, example& source)
{
  if (source.indices.size() == 0)  // making sure we can deal with empty shared example
    return;
  namespace_index* idx = source.indices.end();
  idx--;
  for (; idx >= source.indices.begin(); idx--)
  {
    if (*idx == constant_namespace)
      continue;
    del_example_namespace(target, *idx, source.feature_space[*idx]);
  }
}

void add_example_namespace_from_memory(label_feature_map& lfm, example& ec, size_t lab)
{
  size_t lab_hash = hash_lab(lab);
  features& res = lfm.get(lab, lab_hash);
  if (res.size() == 0)
    return;
  add_example_namespace(ec, static_cast<unsigned char>('l'), res);
}

void del_example_namespace_from_memory(label_feature_map& lfm, example& ec, size_t lab)
{
  size_t lab_hash = hash_lab(lab);
  features& res = lfm.get(lab, lab_hash);
  if (res.size() == 0)
    return;
  del_example_namespace(ec, static_cast<unsigned char>('l'), res);
}

void set_label_features(label_feature_map& lfm, size_t lab, features& fs)
{
  size_t lab_hash = hash_lab(lab);
  if (lfm.contains(lab, lab_hash))
    return;
  lfm.put_after_get(lab, lab_hash, fs);
}

void free_label_features(label_feature_map& lfm)
{
  void* label_iter = lfm.iterator();
  while (label_iter != nullptr)
  {
    features* res = lfm.iterator_get_value(label_iter);
    res->values.delete_v();
    res->indicies.delete_v();
    res->space_names.delete_v();

    label_iter = lfm.iterator_next(label_iter);
  }
  lfm.clear();
  lfm.delete_v();
}
}  // namespace LabelDict