vector_math.hpp

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// -*- mode: c++; indent-tabs-mode: nil; -*-
//
//The Biomolecule Toolkit (BTK) is a C++ library for use in the
//modeling, analysis, and design of biological macromolecules.
//Copyright (C) 2005-2006, Tim Robertson <kid50@users.sourceforge.net>,
//                         Chris Saunders <ctsa@users.sourceforge.net>
//
//This program is free software; you can redistribute it and/or modify
//it under the terms of the GNU Lesser General Public License as published
//by the Free Software Foundation; either version 2.1 of the License, or (at
//your option) any later version.
//
//This program is distributed in the hope that it will be useful,  but
//WITHOUT ANY WARRANTY; without even the implied warranty of'
//MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
//Lesser General Public License for more details.
//
//You should have received a copy of the GNU Lesser General Public License
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#ifndef BTK_MATH_VECTOR_MATH_HPP
#define BTK_MATH_VECTOR_MATH_HPP

#include <cmath>

#include <btk/core/math/btk_vector.hpp>

namespace BTK {
namespace MATH {



inline
BTKVector &
normalize(BTKVector & v)
{
  v /= norm_2(v);
  return v;
}

inline double length(BTKVector const & v) { return norm_2(v); }

inline
BTKVector
cross(BTKVector const & lhs,
      BTKVector const & rhs)
{
  BTKVector temp;

  temp[0] = lhs[1] * rhs[2] - lhs[2] * rhs[1];
  temp[1] = lhs[2] * rhs[0] - lhs[0] * rhs[2];
  temp[2] = lhs[0] * rhs[1] - lhs[1] * rhs[0];

  return temp;
}

BTKVector
project(BTKVector const & a,
        BTKVector const & b);

BTKVector
project_normal(BTKVector const & a,
               BTKVector const & b);

inline
double
cosine_vector_angle(BTKVector const & v1,
                    BTKVector const & v2)
{
  return (prec_inner_prod(v1,v2) / (norm_2(v1) * norm_2(v2)));
}

inline
double
vector_angle(BTKVector const & v1,
             BTKVector const & v2)
{
  return acos(cosine_vector_angle(v1,v2));
}

double
vector_dihedral(BTKVector const & v1,
                BTKVector const & v2,
                BTKVector const & v3);


} // namespace MATH
} // namespace BTK

#endif // BTK_VECTOR_MATH_H

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