// -*- C++ -*-
// SymTensor.h: Symmetric tensor objects (containing six doubles).
//
// Copyright (C) 2008 Jakob Schiotz and Center for Individual
// Nanoparticle Functionality, Department of Physics, Technical
// University of Denmark.  Email: schiotz@fysik.dtu.dk
//
// This file is part of Asap version 3.
// Asap is released under the GNU Lesser Public License (LGPL) version 3.
// However, the parts of Asap distributed within the OpenKIM project
// (including this file) are also released under the Common Development
// and Distribution License (CDDL) version 1.0.
//
// This program is free software: you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public License
// version 3 as published by the Free Software Foundation.  Permission
// to use other versions of the GNU Lesser General Public License may
// granted by Jakob Schiotz or the head of department of the
// Department of Physics, Technical University of Denmark, as
// described in section 14 of the GNU General Public License.
//
// 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
// and the GNU Lesser Public License along with this program.  If not,
// see <http://www.gnu.org/licenses/>.

#ifndef _SYMTENSOR_H
#define _SYMTENSOR_H

namespace ASAPSPACE {

class SymTensor
{
public:
  SymTensor() {};
  /// const indexing
  double operator[](int n) const;
  /// Non-const indexing
  double& operator[](int n);

private:
  double x[6];  ///< The actual data.
};

inline double SymTensor::operator[](int n) const
{
  return x[n];
}

inline double& SymTensor::operator[](int n)
{
  return x[n];
}

} // end namespace

#endif // _SYMTENSOR_H