GRINS::ComputeDistanceJacobian Class Reference

#include <distance_function.h>

Public Member Functions
	ComputeDistanceJacobian ()
	~ComputeDistanceJacobian ()
template<class f >
void	operator() (const libMesh::DenseVector< libMesh::Real > &U, const libMesh::DenseVector< libMesh::Real > &F0, f &F, libMesh::DenseMatrix< libMesh::Real > &dFdU)

Private Attributes
libMesh::DenseVector< libMesh::Real >	Up
libMesh::DenseVector< libMesh::Real >	Fp
libMesh::DenseVector< libMesh::Real >	Um
libMesh::DenseVector< libMesh::Real >	Fm

Detailed Description

This class provides the functionality to compute finite difference Jacobians required when computing the distance function

Definition at line 118 of file distance_function.h.

Constructor & Destructor Documentation

GRINS::ComputeDistanceJacobian::ComputeDistanceJacobian ( )

inline

Definition at line 123 of file distance_function.h.

{}

GRINS::ComputeDistanceJacobian::~ComputeDistanceJacobian ( )

inline

Definition at line 126 of file distance_function.h.

{}

Member Function Documentation

template<class f >

void GRINS::ComputeDistanceJacobian::operator() ( const libMesh::DenseVector< libMesh::Real > &  U, const libMesh::DenseVector< libMesh::Real > &  F0, f &  F, libMesh::DenseMatrix< libMesh::Real > &  dFdU  )

inline

Finite-differenced Jacobian approximation.

Definition at line 132 of file distance_function.h.

References Fp, and Up.

    {

      Up = U;
      Fp.resize(U.size());

      dFdU.resize(U.size(),U.size());

      // compute dF_i/dU_j.
      for (unsigned int j=0; j<U.size(); j++)
        {
          // tell the user's function which component we are perturbing
          // at this iteration.  this information may be used to avoid
          // repeated calculations of values which are known to be
          // unaffected for this perturbation.
          //F.set_perturbed_component(j);

          // define the pertubation for this component
          const libMesh::Real
            pert  = 4.e-8*(std::max (std::abs(U(j)), 1.e-3)); // U can be 0, pertubation cannot

          Up(j) += pert;

          const libMesh::Real                     // note this difference may not strictly be pert
            invpert = 1./(Up(j) - U(j)); // due to truncation error in the preceeding sum.

          // evaluate F at the perturbed state
          F(Up,Fp);

          // remove perturbation for next evaluation
          Up(j) = U(j);

          for (unsigned int i=0; i<U.size(); i++)
            dFdU(i,j) = (Fp(i) - F0(i))*invpert;
        }
    }

Member Data Documentation

libMesh::DenseVector<libMesh::Real> GRINS::ComputeDistanceJacobian::Fm

private

Definition at line 175 of file distance_function.h.

libMesh::DenseVector<libMesh::Real> GRINS::ComputeDistanceJacobian::Fp

private

Definition at line 175 of file distance_function.h.

Referenced by operator()().

libMesh::DenseVector<libMesh::Real> GRINS::ComputeDistanceJacobian::Um

private

Definition at line 175 of file distance_function.h.

libMesh::DenseVector<libMesh::Real> GRINS::ComputeDistanceJacobian::Up

private

Definition at line 175 of file distance_function.h.

Referenced by operator()().

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The documentation for this class was generated from the following file:

• src/utilities/include/grins/distance_function.h