LinearHex.hpp

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#ifndef LINEAR_HEX_HPP
#define LINEAR_HEX_HPP
/**\brief Shape function space for trilinear hexahedron, obtained by a pushforward of the canonical
 * linear (affine) functions. */

#include "moab/ElemEvaluator.hpp"
#include "moab/CN.hpp"

namespace moab
{

class LinearHex
{
  public:
    /** \brief Forward-evaluation of field at parametric coordinates */
    static ErrorCode evalFcn( const double* params,
                              const double* field,
                              const int ndim,
                              const int num_tuples,
                              double* work,
                              double* result );

    /** \brief Reverse-evaluation of parametric coordinates at physical space position */
    static ErrorCode reverseEvalFcn( EvalFcn eval,
                                     JacobianFcn jacob,
                                     InsideFcn ins,
                                     const double* posn,
                                     const double* verts,
                                     const int nverts,
                                     const int ndim,
                                     const double iter_tol,
                                     const double inside_tol,
                                     double* work,
                                     double* params,
                                     int* is_inside );

    /** \brief Evaluate the normal at a specified facet*/
    static ErrorCode normalFcn( const int ientDim,
                                const int facet,
                                const int nverts,
                                const double* verts,
                                double normal[] );

    /** \brief Evaluate the jacobian at a specified parametric position */
    static ErrorCode jacobianFcn( const double* params,
                                  const double* verts,
                                  const int nverts,
                                  const int ndim,
                                  double* work,
                                  double* result );

    /** \brief Forward-evaluation of field at parametric coordinates */
    static ErrorCode integrateFcn( const double* field,
                                   const double* verts,
                                   const int nverts,
                                   const int ndim,
                                   const int num_tuples,
                                   double* work,
                                   double* result );

    /** \brief Function that returns whether or not the parameters are inside the natural space of
     * the element */
    static int insideFcn( const double* params, const int ndim, const double tol );

    static EvalSet eval_set()
    {
        return EvalSet( evalFcn, reverseEvalFcn, normalFcn, jacobianFcn, integrateFcn, (InitFcn)NULL, insideFcn );
    }

    static bool compatible( EntityType tp, int numv, EvalSet& eset )
    {
        if( tp == MBHEX && numv == 8 )
        {
            eset = eval_set();
            return true;
        }
        else
            return false;
    }

  protected:
    /* Preimages of the vertices -- "canonical vertices" -- are known as "corners". */
    static const double corner[8][3];
    static const double gauss[1][2];
    static const unsigned int corner_count = 8;
    static const unsigned int gauss_count  = 1;

};  // class LinearHex

}  // namespace moab

#endif