/**
 *  \file IMP/isd/TALOSRestraint.h
 *  \brief TALOS dihedral restraint between four particles.
 *
 *  Copyright 2007-2013 IMP Inventors. All rights reserved.
 *
 */

#ifndef IMPISD_TALOS_RESTRAINT_H
#define IMPISD_TALOS_RESTRAINT_H

#include <IMP/isd/isd_config.h>
#include "Scale.h"
#include "vonMisesSufficient.h"

#include <IMP/Restraint.h>
#include <IMP/Particle.h>

IMPISD_BEGIN_NAMESPACE

//! phi/psi dihedral restraint between four particles, using data from TALOS.
/** The likelihood is
       \f[
       f(\chi_{exp}^1,\cdots,\chi_{exp}^N|\chi(X),\kappa,I)
        = \frac{1}{2\pi I_0(\kappa)^N}
        \exp \left(R_0 \kappa \cos (\chi_{exp}-\chi(X)) \right)
      \f]
    where the sufficient statistics are \f$N\f$ the number of observations,
    \f$R\f$ and \f$\chi_{exp}\f$.
    \see vonMisesSufficient.h for further detail.
*/
class IMPISDEXPORT TALOSRestraint : public Restraint
{
public:

  //! Create restraint from a list of particles and the data.
  /** \param[in] p list of 4 particles that make the dihedral angle.
      \param[in] data list of observations for that angle.
      \param[in] kappa Pointer to the \f$\kappa\f$ concentration particle.
   */
  TALOSRestraint(Particles p, Floats data, Particle *kappa);

  //! Create restraint from 4 particles and the data.
  /** \param[in] p1 Pointer to first particle in dihedral restraint.
      \param[in] p2 Pointer to second particle in dihedral restraint.
      \param[in] p3 Pointer to third particle in dihedral restraint.
      \param[in] p4 Pointer to fourth particle in dihedral restraint.
      \param[in] data list of observations for that angle.
      \param[in] kappa Pointer to the \f$\kappa\f$ concentration particle.
   */
  TALOSRestraint(Particle* p1, Particle* p2, Particle* p3, Particle *p4,
                 Floats data, Particle *kappa);

  //! Create restraint from a list of particles and the sufficient statistics.
  /** \param[in] p list of 4 particles that make the dihedral angle.
      \param[in] N Number of observations
      \param[in] R0 component on the x axis
      \param[in] chiexp average observed angle.
      \param[in] kappa Pointer to the \f$\kappa\f$ concentration particle.
   */
  TALOSRestraint(Particles p, unsigned N, double R0, double chiexp,
                 Particle *kappa);

  //! Create restraint from 4 particles and the sufficient statistics.
  /** \param[in] p1 Pointer to first particle in dihedral restraint.
      \param[in] p2 Pointer to second particle in dihedral restraint.
      \param[in] p3 Pointer to third particle in dihedral restraint.
      \param[in] p4 Pointer to fourth particle in dihedral restraint.
      \param[in] N Number of observations
      \param[in] R0 component on the x axis
      \param[in] chiexp average observed angle.
      \param[in] kappa Pointer to the \f$\kappa\f$ concentration particle.
   */
  TALOSRestraint(Particle* p1, Particle* p2, Particle* p3, Particle *p4,
          unsigned N, double R0, double chiexp, Particle *kappa);


  //! Call for probability
  double get_probability() const
  {
    return exp(-unprotected_evaluate(nullptr));
  }

  double get_R0() const
  {
      return mises_->get_R0();
  }

  double get_chiexp() const
  {
      return mises_->get_chiexp();
  }

  IMP_RESTRAINT(TALOSRestraint);

private:
  IMP::Pointer<Particle> p_[4];
  IMP::Pointer<Particle> kappa_;
  IMP::Pointer<vonMisesSufficient> mises_;
};

IMPISD_END_NAMESPACE

#endif  /* IMPISD_TALOS_RESTRAINT_H */