Vector2.hpp

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 * SUPPORT OPEN SCIENCE!  If you use OpenMD or its source code in your
 * research, please cite the appropriate papers when you publish your
 * work.  Good starting points are:
 *
 * [1] Meineke, et al., J. Comp. Chem. 26, 252-271 (2005).
 * [2] Fennell & Gezelter, J. Chem. Phys. 124, 234104 (2006).
 * [3] Sun, Lin & Gezelter, J. Chem. Phys. 128, 234107 (2008).
 * [4] Vardeman, Stocker & Gezelter, J. Chem. Theory Comput. 7, 834 (2011).
 * [5] Kuang & Gezelter, Mol. Phys., 110, 691-701 (2012).
 * [6] Lamichhane, Gezelter & Newman, J. Chem. Phys. 141, 134109 (2014).
 * [7] Lamichhane, Newman & Gezelter, J. Chem. Phys. 141, 134110 (2014).
 * [8] Bhattarai, Newman & Gezelter, Phys. Rev. B 99, 094106 (2019).
 */
 
#ifndef MATH_VECTOR2_HPP
#define MATH_VECTOR2_HPP
 
#include <cassert>
#include <cmath>
 
#include "Vector.hpp"
 
namespace OpenMD {
 
  template<typename Real>
  class Vector2 : public Vector<Real, 2> {
  public:
    typedef Real ElemType;
    typedef Real* ElemPoinerType;
    Vector2() : Vector<Real, 2>() {}
 
    /** Constructs and initializes a Vector2 from x and y coordinates */
    inline Vector2(Real x, Real y) {
      this->data_[0] = x;
      this->data_[1] = y;
    }
 
    /** Constructs and initializes from an array*/
    inline Vector2(Real* array) : Vector<Real, 2>(array) {}
 
    inline Vector2(const Vector<Real, 2>& v) : Vector<Real, 2>(v) {}
 
    inline Vector2<Real>& operator=(const Vector<Real, 2>& v) {
      if (this == &v) { return *this; }
      Vector<Real, 2>::operator=(v);
      return *this;
    }
 
    /**
     * Returns reference of the first element of Vector2.
     * @return reference of the first element of Vector2
     */
    inline Real& x() { return this->data_[0]; }
 
    /**
     * Returns the first element of Vector2.
     * @return  the first element of Vector2
     */
    inline Real x() const { return this->data_[0]; }
 
    /**
     * Returns reference of the second element of Vector2.
     * @return reference of the second element of Vector2
     */
    inline Real& y() { return this->data_[1]; }
 
    /**
     * Returns  the second element of Vector2.
     * @return c the second element of Vector2
     */
    inline Real y() const { return this->data_[1]; }
  };
 
  /**
   * Returns the linear indexing for size_t vectors. Compare to
   * Rapaport's VLinear
   *
   * @param p first vector
   * @param s second vector
   */
  inline std::size_t Vlinear(const Vector2<std::size_t>& p,
                             const Vector2<std::size_t>& s) {
    return std::size_t(p.y() * s.x() + p.x());
  }
 
  typedef Vector2<int> Vector2i;
 
  typedef Vector2<RealType> Vector2d;
 
  const Vector2d V2Zero(0.0, 0.0);
  const Vector2d V2X(1.0, 0.0);
  const Vector2d V2Y(0.0, 1.0);
 
}  // namespace OpenMD
 
#endif