// $Id: mesh_function.h 2834 2008-05-08 13:18:54Z roystgnr $// The libMesh Finite Element Library.// Copyright (C) 2002-2007  Benjamin S. Kirk, John W. Peterson  // 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 along with this library; if not, write to the Free Software// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA#ifndef __mesh_function_h__#define __mesh_function_h__// C++ includes#include <vector>// Local Includes#include "function_base.h"#include "dense_vector.h"#include "vector_value.h"#include "tensor_value.h"#include "tree_base.h"// Forward Declarationstemplate <typename T> class DenseVector;class EquationSystems;template <typename T> class NumericVector;class DofMap;class PointLocatorBase;/** * This class provides function-like objects for data * distributed over a mesh.   * * @author Daniel Dreyer, 2003 */// ------------------------------------------------------------// MeshFunction class definitionclass MeshFunction : public FunctionBase{public:  /**   * Constructor for mesh based functions with vectors   * as return value.  Optionally takes a master function.   * If the MeshFunction is to be evaluated outside of the   * local partition of the mesh, then both the mesh in   * \p eqn_systems and the coefficient vector \p vec   * should be serialized.   */  MeshFunction (const EquationSystems& eqn_systems,		const NumericVector<Number>& vec,		const DofMap& dof_map,		const std::vector<unsigned int>& vars,		const FunctionBase* master=NULL);  /**   * Constructor for mesh based functions with a number   * as return value.  Optionally takes a master function.   * If the MeshFunction is to be evaluated outside of the   * local partition of the mesh, then both the mesh in   * \p eqn_systems and the coefficient vector \p vec   * should be serialized.   */  MeshFunction (const EquationSystems& eqn_systems,		const NumericVector<Number>& vec,		const DofMap& dof_map,		const unsigned int var,		const FunctionBase* master=NULL);  /**   * Destructor.   */  ~MeshFunction ();  /**   * The actual initialization process.   * specifies the method to use when building a \p PointLocator   */  void init () { this->init(Trees::NODES); };  /**   * The actual initialization process.  Takes an optional argument which   * specifies the method to use when building a \p PointLocator   */  void init (const Trees::BuildType point_locator_build_type);  /**   * Clears the function.   */  void clear ();  /**   * @returns the value of variable 0 at point   * \p p and for \p time, which defaults to zero.   */  Number operator() (const Point& p, 		     const Real time=0.);  /**   * @returns the first derivatives of variable 0 at point   * \p p and for \p time, which defaults to zero.   */  Gradient gradient (const Point& p, 		     const Real time=0.);#ifdef ENABLE_SECOND_DERIVATIVES  /**   * @returns the second derivatives of variable 0 at point   * \p p and for \p time, which defaults to zero.   */  Tensor hessian (const Point& p, 		  const Real time=0.);#endif  /**   * Computes values at coordinate \p p and for time \p time, which   * defaults to zero.   */  void operator() (const Point& p,		   const Real time,		   DenseVector<Number>& output);  /**   * Computes gradients at coordinate \p p and for time \p time, which   * defaults to zero.   */  void gradient (const Point& p,		 const Real time,		 std::vector<Gradient>& output);  /**   * Computes gradients at coordinate \p p and for time \p time, which   * defaults to zero.   */  void hessian (const Point& p,		const Real time,		std::vector<Tensor>& output);  /**   * Returns the current \p PointLocator object, for you might want to   * use it elsewhere.  The \p MeshFunction object must be initialized   * before.   */  const PointLocatorBase& get_point_locator (void) const;  /**   * Enables out-of-mesh mode.  In this mode, if asked for a point   * that is not contained in any element, the \p MeshFunction will   * return the given \p value instead of crashing.  This mode is off   * per default.  If you use a master mesh function and you want to   * enable this mode, you will have to enable it for the master mesh   * function as well and for all mesh functions that have the same   * master mesh function.  You may, however, specify different   * values.   */  void enable_out_of_mesh_mode(const DenseVector<Number>& value);  /**   * Enables out-of-mesh mode.  In this mode, if asked for a point   * that is not contained in any element, the \p MeshFunction will   * return the given \p value instead of crashing.  This mode is off   * per default.  If you use a master mesh function and you want to   * enable this mode, you will have to enable it for the master mesh   * function as well and for all mesh functions that have the same   * master mesh function.  You may, however, specify different   * values.   */  void enable_out_of_mesh_mode(const Number& value);  /**   * Disables out-of-mesh mode.  This is also the default.   */  void disable_out_of_mesh_mode(void);protected:  /**   * The equation systems handler, from which   * the data are gathered.   */  const EquationSystems& _eqn_systems;  /**   * A reference to the vector that holds the data   * that is to be interpolated.   */  const NumericVector<Number>& _vector;  /**   * Need access to the \p DofMap of the other system.   */  const DofMap& _dof_map;  /**   * The indices of the variables within the other system    * for which data are to be gathered.   */  const std::vector<unsigned int> _system_vars;  /**   * A point locator is needed to locate the   * points in the mesh.   */  PointLocatorBase* _point_locator;  /**   * \p true if out-of-mesh mode is enabled.  See \p   * enable_out_of_mesh_mode() for more details.  Default is \p false.   */  bool _out_of_mesh_mode;  /**   * Value to return outside the mesh if out-of-mesh mode is enabled.   * See \p enable_out_of_mesh_mode() for more details.   */  DenseVector<Number> _out_of_mesh_value;};// ------------------------------------------------------------// MeshFunction inline methods#endif