/**
 *  \file Linear.h    \brief A linear function.
 *
 *  Copyright 2007-2010 IMP Inventors. All rights reserved.
 */

#ifndef IMPCORE_LINEAR_H
#define IMPCORE_LINEAR_H

#include "core_config.h"
#include <IMP/UnaryFunction.h>

IMPCORE_BEGIN_NAMESPACE

//! %Linear function
/** \note The offset is not meaningful for optimization, but does
    make the displayed energies nicer.
 */
class Linear : public UnaryFunction
{
public:
  //! Create with the given offset and slope.
  Linear(double offset, double slope) : slope_(slope), offset_(offset) {}

  IMP_UNARY_FUNCTION_INLINE(Linear,
                            (feature-offset_)*slope_,
                            slope_,
                            "Linear: " << slope_ << ", " << offset_
                            << std::endl);
  void set_slope(double f) {
    slope_=f;
  }

  void set_offset(double f) {
    offset_=f;
  }

private:
  double slope_, offset_;
};

IMPCORE_END_NAMESPACE

#endif  /* IMPCORE_LINEAR_H */