/* *****************************************************************
    MESQUITE -- The Mesh Quality Improvement Toolkit

    Copyright 2006 Sandia National Laboratories.  Developed at the
    University of Wisconsin--Madison under SNL contract number
    624796.  The U.S. Government and the University of Wisconsin
    retain certain rights to this software.

    This library 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 library 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
    (lgpl.txt) along with this library; if not, write to the Free Software
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

    (2006) kraftche@cae.wisc.edu

  ***************************************************************** */

/** \file TetLagrangeShape.hpp
 *  \brief
 *  \author Jason Kraftcheck
 */

#ifndef MSQ_TET_LAGRANGE_SHAPE_HPP
#define MSQ_TET_LAGRANGE_SHAPE_HPP

#include "Mesquite.hpp"
#include "MappingFunction.hpp"

namespace MBMesquite
{

/**\brief Lagrange shape function for tetrahedral elements
 *
 * This class implements the MappingFunction interface, providing
 * a Lagrange shape function for a 10-node tet.
 *
 * \f$\vec{x}(r,s,t) = sum_{i=0}^{n-1} N_i(r,s,t) \vec{x_i}\f$
 *
 * \f$N_1 = u(2u - 1)\f$
 *
 * \f$N_2 = r(2r - 1)\f$
 *
 * \f$N_3 = s(2s - 1)\f$
 *
 * \f$N_4 = t(2t - 1)\f$
 *
 * \f$N_5 = 4ru\f$
 *
 * \f$N_6 = 4rs\f$
 *
 * \f$N_7 = 4su\f$
 *
 * \f$N_8 = 4tu\f$
 *
 * \f$N_9 = 4rt\f$
 *
 * \f$N_10 = 4st\f$
 *
 * \f$u = 1 - r - s - t\f$
 */
class MESQUITE_EXPORT TetLagrangeShape : public MappingFunction3D
{
  public:
    virtual EntityTopology element_topology() const;

    virtual int num_nodes() const;

    virtual NodeSet sample_points( NodeSet higher_order_nodes ) const;

    virtual void coefficients( Sample location, NodeSet nodeset, double* coeff_out, size_t* indices_out,
                               size_t& num_coeff_out, MsqError& err ) const;

    virtual void derivatives( Sample location, NodeSet nodeset, size_t* vertex_indices_out,
                              MsqVector< 3 >* d_coeff_d_xi_out, size_t& num_vtx, MsqError& err ) const;

    virtual void ideal( Sample location, MsqMatrix< 3, 3 >& jacobian_out, MsqError& err ) const;
};

}  // namespace MBMesquite

#endif
