Vec3D.h

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// n2p2 - A neural network potential package
// Copyright (C) 2018 Andreas Singraber (University of Vienna)
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 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 General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
#ifndef VEC3D_H
#define VEC3D_H
 
#include <cstddef>   // std::size_t
#include <cmath>     // sqrt
#include <stdexcept> // std::runtime_error
 
namespace nnp
{
 
struct Vec3D
{
    double r[3];
 
    Vec3D();
    Vec3D(double x, double y, double z);
    Vec3D(Vec3D const& source);
    Vec3D&        operator=(Vec3D const& rhs);
    Vec3D&        operator+=(Vec3D const& v);
    Vec3D&        operator-=(Vec3D const& v);
    Vec3D&        operator*=(double const a);
    Vec3D&        operator/=(double const a);
    double        operator*(Vec3D const& v) const;
    double&       operator[](std::size_t const index);
    double const& operator[](std::size_t const index) const;
    bool          operator==(Vec3D const& rhs) const;
    bool          operator!=(Vec3D const& rhs) const;
    double        norm() const;
    double        norm2() const;
    double        l1norm() const;
    Vec3D&        normalize();
    Vec3D         cross(Vec3D const& v) const;
};
 
Vec3D operator+(Vec3D lhs, Vec3D const& rhs);
Vec3D operator-(Vec3D lhs, Vec3D const& rhs);
Vec3D operator-(Vec3D v);
Vec3D operator*(Vec3D v, double const a);
Vec3D operator/(Vec3D v, double const a);
Vec3D operator*(double const a, Vec3D v);
 
// Inlined function definitions //
 
inline Vec3D::Vec3D()
{
    r[0] = 0.0;
    r[1] = 0.0;
    r[2] = 0.0;
}
 
inline Vec3D::Vec3D(double x, double y, double z)
{
    r[0] = x;
    r[1] = y;
    r[2] = z;
}
 
inline Vec3D::Vec3D(Vec3D const& source)
{
    r[0] = source.r[0];
    r[1] = source.r[1];
    r[2] = source.r[2];
}
 
inline Vec3D& Vec3D::operator=(Vec3D const& rhs)
{
    r[0] = rhs.r[0];
    r[1] = rhs.r[1];
    r[2] = rhs.r[2];
 
    return *this;
}
 
inline Vec3D& Vec3D::operator+=(Vec3D const& rhs)
{
    r[0] += rhs.r[0];
    r[1] += rhs.r[1];
    r[2] += rhs.r[2];
 
    return *this;
}
 
inline Vec3D& Vec3D::operator-=(Vec3D const& rhs)
{
    r[0] -= rhs.r[0];
    r[1] -= rhs.r[1];
    r[2] -= rhs.r[2];
 
    return *this;
}
 
inline Vec3D& Vec3D::operator*=(double const a)
{
    r[0] *= a;
    r[1] *= a;
    r[2] *= a;
 
    return *this;
}
 
inline Vec3D& Vec3D::operator/=(double const a)
{
    *this *= 1.0 / a;
 
    return *this;
}
 
inline double Vec3D::operator*(Vec3D const& v) const
{
    return r[0] * v.r[0] + r[1] * v.r[1] + r[2] * v.r[2];
}
 
// Doxygen requires namespace prefix for arguments...
inline double& Vec3D::operator[](std::size_t const index)
{
    if (index < 3) return r[index];
    else
    {
        throw std::runtime_error("ERROR: 3D vector has only three"
                                 " components.\n");
    }
}
 
// Doxygen requires namespace prefix for arguments...
inline double const& Vec3D::operator[](std::size_t const index) const
{
    if (index < 3) return r[index];
    else
    {
        throw std::runtime_error("ERROR: 3D vector has only three"
                                 " components.\n");
    }
}
 
inline bool Vec3D::operator==(Vec3D const& rhs) const
{
    if (r[0] != rhs.r[0]) return false;
    if (r[1] != rhs.r[1]) return false;
    if (r[2] != rhs.r[2]) return false;
    return true;
}
 
inline bool Vec3D::operator!=(Vec3D const& rhs) const
{
    return !(*this == rhs);
}
 
inline double Vec3D::norm() const
{
    return sqrt(r[0] * r[0] + r[1] * r[1] + r[2] * r[2]);
}
 
inline double Vec3D::norm2() const
{
    return r[0] * r[0] + r[1] * r[1] + r[2] * r[2];
}
 
inline double Vec3D::l1norm() const
{
    return fabs(r[0]) + fabs(r[1]) + fabs(r[2]);
}
 
inline Vec3D& Vec3D::normalize()
{
    double n = norm();
    r[0] /= n;
    r[1] /= n;
    r[2] /= n;
 
    return *this;
}
 
inline Vec3D Vec3D::cross(Vec3D const& v) const
{
    Vec3D w;
 
    w.r[0] = r[1] * v.r[2] - r[2] * v.r[1];
    w.r[1] = r[2] * v.r[0] - r[0] * v.r[2];
    w.r[2] = r[0] * v.r[1] - r[1] * v.r[0];
 
    return w;
}
 
inline Vec3D operator+(Vec3D lhs, Vec3D const& rhs)
{
    return lhs += rhs;
}
 
inline Vec3D operator-(Vec3D lhs, Vec3D const& rhs)
{
    return lhs -= rhs;
}
 
inline Vec3D operator-(Vec3D v)
{
    v *= -1.0;
    return v;
}
 
inline Vec3D operator*(Vec3D v, double const a)
{
    return v *= a;
}
 
inline Vec3D operator/(Vec3D v, double const a)
{
    return v /= a;
}
 
inline Vec3D operator*(double const a, Vec3D v)
{
    return v *= a;
}
 
}
 
#endif