fern.h

/*
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 *
 *  Point Cloud Library (PCL) - www.pointclouds.org
 *  Copyright (c) 2010-2011, Willow Garage, Inc.
 *
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 *     notice, this list of conditions and the following disclaimer.
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 *     copyright notice, this list of conditions and the following
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 *     with the distribution.
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 *     contributors may be used to endorse or promote products derived
 *     from this software without specific prior written permission.
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 */
 
#pragma once
 
#include <pcl/common/common.h>
 
#include <istream>
#include <ostream>
 
namespace pcl {
 
/** Class representing a Fern. */
template <class FeatureType, class NodeType>
class PCL_EXPORTS Fern {
public:
  /** Constructor. */
  Fern() : num_of_decisions_(0), features_(0), thresholds_(0), nodes_(1) {}
 
  /** Initializes the fern.
   *
   * \param num_of_decisions the number of decisions taken to access the nodes
   */
  void
  initialize(const std::size_t num_of_decisions)
  {
    num_of_decisions_ = num_of_decisions;
    features_.resize(num_of_decisions_);
    thresholds_.resize(num_of_decisions_, std::numeric_limits<float>::quiet_NaN());
    nodes_.resize(0x1 << num_of_decisions_);
  }
 
  /** Returns the number of nodes the Fern has. */
  inline std::size_t
  getNumOfNodes()
  {
    return 0x1U << num_of_decisions_;
  }
 
  /** Returns the number of features the Fern has. */
  inline std::size_t
  getNumOfFeatures()
  {
    return num_of_decisions_;
  }
 
  /** Serializes the fern.
   *
   * \param[out] stream the destination for the serialization
   */
  void
  serialize(::std::ostream& stream) const
  {
    // const int tmp_value = static_cast<int> (num_of_decisions_);
    // stream.write (reinterpret_cast<char*> (&tmp_value), sizeof (tmp_value));
    stream.write(reinterpret_cast<const char*>(&num_of_decisions_),
                 sizeof(num_of_decisions_));
 
    for (auto& feature : features_) {
      feature.serialize(stream);
    }
 
    for (const auto& threshold : thresholds_) {
      stream.write(reinterpret_cast<const char*>(&threshold), sizeof(threshold));
    }
 
    for (auto& node : nodes_) {
      node.serialize(stream);
    }
  }
 
  /** Deserializes the fern.
   *
   * \param[in] stream the source for the deserialization
   */
  void
  deserialize(::std::istream& stream)
  {
    stream.read(reinterpret_cast<char*>(&num_of_decisions_), sizeof(num_of_decisions_));
 
    features_.resize(num_of_decisions_);
    thresholds_.resize(num_of_decisions_);
    nodes_.resize(0x1 << num_of_decisions_);
 
    for (auto& feature : features_) {
      feature.deserialize(stream);
    }
 
    for (const auto& threshold : thresholds_) {
      stream.read(reinterpret_cast<char*>(&(threshold)), sizeof(threshold));
    }
 
    for (auto& node : nodes_) {
      node.deserialize(stream);
    }
  }
 
  /** Access operator for nodes.
   *
   * \param node_index the index of the node to access
   */
  inline NodeType&
  operator[](const std::size_t node_index)
  {
    return nodes_[node_index];
  }
 
  /** Access operator for nodes.
   *
   * \param node_index the index of the node to access
   */
  inline const NodeType&
  operator[](const std::size_t node_index) const
  {
    return nodes_[node_index];
  }
 
  /** Access operator for features.
   *
   * \param feature_index the index of the feature to access
   */
  inline FeatureType&
  accessFeature(const std::size_t feature_index)
  {
    return features_[feature_index];
  }
 
  /** Access operator for features.
   *
   * \param feature_index the index of the feature to access
   */
  inline const FeatureType&
  accessFeature(const std::size_t feature_index) const
  {
    return features_[feature_index];
  }
 
  /** Access operator for thresholds.
   *
   * \param threshold_index the index of the threshold to access
   */
  inline float&
  accessThreshold(const std::size_t threshold_index)
  {
    return thresholds_[threshold_index];
  }
 
  /** Access operator for thresholds.
   *
   * \param threshold_index the index of the threshold to access
   */
  inline const float&
  accessThreshold(const std::size_t threshold_index) const
  {
    return thresholds_[threshold_index];
  }
 
private:
  /** The number of decisions. */
  std::size_t num_of_decisions_;
  /** The list of Features used to make the decisions. */
  std::vector<FeatureType> features_;
  /** The list of thresholds used to make the decisions. */
  std::vector<float> thresholds_;
  /** The list of Nodes accessed by the Fern. */
  std::vector<NodeType> nodes_;
};
 
} // namespace pcl