source: src/Fragmentation/Exporters/SaturationDistanceMaximizer.hpp@ fba720

/*
 * SaturationDistanceMaximizer.hpp
 *
 *  Created on: Jul 27, 2014
 *      Author: heber
 */

#ifndef SATURATIONDISTANCEMAXIMIZER_HPP_
#define SATURATIONDISTANCEMAXIMIZER_HPP_

// include config.h
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include <vector>

#include <gsl/gsl_vector.h>

#include "SaturatedBond.hpp"

class SaturationDistanceMaximizerTest;

/** This class encapsulates the minimizing/maximization performed to find the
 * best angles alpha for a vector of SaturatedBonds.
 */
class SaturationDistanceMaximizer
{
public:
  struct Advocate;

  //!> typedef for a vector of SaturatedBonds
  typedef std::vector<SaturatedBond::ptr> PositionContainers_t;
  //!> typedef for the positions per saturated bond
  typedef std::vector< SaturatedBond::positions_t > position_bins_t;

  SaturationDistanceMaximizer(PositionContainers_t &_PositionContainers) :
    PositionContainers(_PositionContainers)
  {}
  ~SaturationDistanceMaximizer() {}

  /** Maximizes the distances between the saturation hydrogens for a number of
   * SaturedBonds.
   *
   * We maximize the function \f$ \sum_{i<j} \frac{1}{ || x_i - x_j ||^2} \f$.
   */
  void operator()();

  /** Requests positions from each SaturatedBond and places it into vector.
   *
   * \return vector of tuples of positions
   */
  position_bins_t getAllPositionBins() const;

private:
  //!> make advocate friend
  friend struct Advocate;
  //!> make unit tests friend
  friend class SaturationDistanceMaximizerTest;

  /** Evaluates the penalty function over the current positions.
   *
   * \return \f$ \sum_{i<j} \frac{1}{ || x_i - x_j ||^2} \f$
   */
  double calculatePenality() const;

  /** Evaluates the gradient with respect to the angles (i.e. per bin only!)
   *
   * \return tuple with amount of change per bin
   */
  std::vector<double> calculatePenalityGradient() const;

  /** Getter for the alphas of each SaturatedBond.
   *
   * \return vector with all alphas
   */
  std::vector<double> getAlphas() const;

  /** Helper function to set the angles alpha of each SaturatedBond from the
   * components of a gsl_vector \a *x.
   *
   * \param x components containing alpha per bond
   */
  void setAlphas(const gsl_vector *x);

  /** Getter for the advocate to be handed over to other functions or classes.
   *
   * \return ptr to advocate
   */
  Advocate* getAdvocate();

public:
  /** This class is friend and may call penalty functions.
   *
   * This class is private and only SaturationDistanceMaximizer is its friend.
   * Hence, it has total control of who may call its function by instantiating
   * this advocate object abd handing it to someone else (e.g. a function).
   *
   */
  class Advocate
  {
  private:
    friend class SaturationDistanceMaximizer;

    Advocate(
        SaturationDistanceMaximizer &_maximizer) :
          maximizer(_maximizer)
    {}

  public:
    double calculatePenality() const
    {
      return maximizer.calculatePenality();
    }

    /** Evaluates the gradient with respect to the angles (i.e. per bin only!)
     *
     * \return tuple with amount of change per bin
     */
    std::vector<double> calculatePenalityGradient() const
    {
      return maximizer.calculatePenalityGradient();
    }

    /** Helper function to set the angles alpha of each SaturatedBond from the
     * components of a gsl_vector \a *x.
     *
     * \param x components containing alpha per bond
     */
    void setAlphas(const gsl_vector *x)
    {
      maximizer.setAlphas(x);
    }

  private:
    //!> internal instance for functionc alls
    SaturationDistanceMaximizer &maximizer;
  };

private:
  //!> Vectors with all SaturatedBonds belonging to the central atom to saturate
  PositionContainers_t &PositionContainers;
};



#endif /* SATURATIONDISTANCEMAXIMIZER_HPP_ */