/**
 *  \file IMP/core/NormalMover.h
 *  \brief A modifier which perturbs a point with a normal distribution.
 *
 *  Copyright 2007-2013 IMP Inventors. All rights reserved.
 *
 */

#ifndef IMPCORE_NORMAL_MOVER_H
#define IMPCORE_NORMAL_MOVER_H

#include <IMP/core/core_config.h>
#include "MonteCarloMover.h"

IMPCORE_BEGIN_NAMESPACE

//! Modify a set of continuous variables using a normal distribution.
/** \see MonteCarlo
 */
class IMPCOREEXPORT NormalMover : public MonteCarloMover
{
  ParticleIndexes pis_;
  FloatKeys keys_;
  Float stddev_;
  algebra::VectorKDs originals_;

  void initialize(ParticleIndexes pis,
                  FloatKeys keys,
                  double radius);
public:
  NormalMover(Model *m, ParticleIndex pi,
            const FloatKeys &vars, double stddev);
  //! Move the x,y,z coordinates
  NormalMover(Model *m, ParticleIndex pi, double stddev);
#ifndef IMP_DOXYGEN
  /**  \param[in] sc The set of particles to perturb.
       \param[in] vars The variables to use (normally the keys for x,y,z)
       \param[in] sigma The standard deviation to use.
   */
  NormalMover(const ParticlesTemp &sc,
              const FloatKeys &vars,
              Float sigma);

  NormalMover(const ParticlesTemp &sc,
              Float radius);
#endif

  void set_sigma(Float sigma) {
    IMP_USAGE_CHECK(sigma > 0, "Sigma must be positive");
    stddev_=sigma;
  }

  Float get_sigma() const {
    return stddev_;
  }

protected:
  virtual kernel::ModelObjectsTemp do_get_inputs() const IMP_OVERRIDE;
  virtual MonteCarloMoverResult do_propose() IMP_OVERRIDE;
  virtual void do_reject() IMP_OVERRIDE;
  IMP_OBJECT_METHODS(NormalMover);
};

IMPCORE_END_NAMESPACE

#endif  /* IMPCORE_NORMAL_MOVER_H */