/*=========================================================================

  Program:   Insight Segmentation & Registration Toolkit

  Copyright (c) 2002 Insight Consortium. All rights reserved.
  See ITKCopyright.txt or http://www.itk.org/HTML/Copyright.htm for details.

     This software is distributed WITHOUT ANY WARRANTY; without even
     the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
     PURPOSE.  See the above copyright notices for more information.

=========================================================================*/

#ifndef __itkFEMElement3DMembrane1DOF_h
#define __itkFEMElement3DMembrane1DOF_h

#include "itkFEMElementBase.h"
#include "itkFEMMaterialLinearElasticity.h"

namespace itk
{
namespace fem
{
/**
 * \class Element3DMembrane1DOF
 * \brief Class that is used to define a membrane energy problem in 3D space.
 *
 * This class only defines the physics of the problem. Use his class together
 * with element classes that specify the geometry to fully define the element.
 *
 * You can specify one template parameter:
 *
 *   TBaseClass - Class from which Element3DMembrane1DOF is derived. TBaseClass must
 *                be derived from the Element base class. This enables you
 *                to use this class at any level of element definition.
 *                If not specified, it defaults to the Element base class.
 */
template <typename TBaseClass = Element>
class Element3DMembrane1DOF : public TBaseClass
{
  FEM_ABSTRACT_CLASS(Element3DMembrane1DOF, TBaseClass)
public:
  // Repeat the required typedefs and enums from parent class
  typedef typename Superclass::Float      Float;
  typedef typename Superclass::MatrixType MatrixType;
  typedef typename Superclass::VectorType VectorType;

  /**
   * Read data for this class from input stream
   */
  virtual void
  Read(std::istream &, void * info);

  /**
   * Write this class to output stream
   */
  virtual void
  Write(std::ostream & f) const;

  /**
   * Default constructor only clears the internal storage
   */
  Element3DMembrane1DOF();

  // ////////////////////////////////////////////////////////////////////////
  /*
   * Methods related to the physics of the problem.
   */

  /**
   * Compute the B matrix.
   */
  virtual void
  GetStrainDisplacementMatrix(MatrixType & B, const MatrixType & shapeDgl) const;

  /**
   * Compute the D matrix.
   */
  virtual void
  GetMaterialMatrix(MatrixType & D) const;

  /**
   * Compute the mass matrix specific for 3D membrane problems.
   */
  void
  GetMassMatrix(MatrixType & Me) const;

  /**
   * 3D membrane elements have 3 DOFs per node.
   */
  virtual unsigned int
  GetNumberOfDegreesOfFreedomPerNode(void) const
  {
    return 3;
  }

  virtual void
  GetStiffnessMatrix(MatrixType & Ke) const;

public:
  /**
   * Pointer to material properties of the element
   */
  MaterialLinearElasticity::ConstPointer m_mat;
  virtual Material::ConstPointer
  GetMaterial(void) const
  {
    return m_mat;
  }

  virtual void
  SetMaterial(Material::ConstPointer mat_)
  {
    m_mat = dynamic_cast<const MaterialLinearElasticity *>(&*mat_);
  }
}; // class Element3DMembrane1DOF

#ifdef _MSC_VER
// Declare a static dummy function to prevent a MSVC 6.0 SP5 from crashing.
// I have no idea why things don't work when this is not declared, but it
// looks like this declaration makes compiler forget about some of the
// troubles it has with templates.
static void
Dummy();

#endif // #ifdef _MSC_VER
} // namespace fem
} // namespace itk

#ifndef ITK_MANUAL_INSTANTIATION
#  include "itkFEMElement3DMembrane1DOF.hxx"
#endif

#endif // #ifndef __itkFEMElement3DMembrane1DOF_h
