Matrix-based diagonal preconditioner. More...

#include <general_purpose_preconditioners.h>

Inheritance diagram for oomph::MatrixBasedDiagPreconditioner:

Public Member Functions
	MatrixBasedDiagPreconditioner ()
	Constructor (empty) More...

	~MatrixBasedDiagPreconditioner ()
	Destructor (empty) More...

	MatrixBasedDiagPreconditioner (const MatrixBasedDiagPreconditioner &)=delete
	Broken copy constructor. More...

void	operator= (const MatrixBasedDiagPreconditioner &)=delete
	Broken assignment operator. More...

void	preconditioner_solve (const DoubleVector &r, DoubleVector &z)
	Apply preconditioner to z, i.e. z=D^-1. More...

void	setup ()

Public Member Functions inherited from oomph::Preconditioner
	Preconditioner ()
	Constructor. More...

	Preconditioner (const Preconditioner &)=delete
	Broken copy constructor. More...

void	operator= (const Preconditioner &)=delete
	Broken assignment operator. More...

virtual	~Preconditioner ()
	Destructor (empty) More...

virtual void	preconditioner_solve_transpose (const DoubleVector &r, DoubleVector &z)

void	setup (DoubleMatrixBase *matrix_pt)

void	setup (const Problem problem_pt, DoubleMatrixBase matrix_pt)

void	enable_silent_preconditioner_setup ()
	Set up the block preconditioner quietly! More...

void	disable_silent_preconditioner_setup ()
	Be verbose in the block preconditioner setup. More...

virtual void	clean_up_memory ()
	Clean up memory (empty). Generic interface function. More...

virtual DoubleMatrixBase *	matrix_pt () const
	Get function for matrix pointer. More...

virtual void	set_matrix_pt (DoubleMatrixBase *matrix_pt)
	Set the matrix pointer. More...

virtual const OomphCommunicator *	comm_pt () const
	Get function for comm pointer. More...

virtual void	set_comm_pt (const OomphCommunicator *const comm_pt)
	Set the communicator pointer. More...

double	setup_time () const
	Returns the time to setup the preconditioner. More...

virtual void	turn_into_subsidiary_block_preconditioner (BlockPreconditioner< CRDoubleMatrix > *master_block_prec_pt, const Vector< unsigned > &doftype_in_master_preconditioner_coarse)

virtual void	turn_into_subsidiary_block_preconditioner (BlockPreconditioner< CRDoubleMatrix > *master_block_prec_pt, const Vector< unsigned > &doftype_in_master_preconditioner_coarse, const Vector< Vector< unsigned >> &doftype_coarsen_map_coarse)

Public Member Functions inherited from oomph::DistributableLinearAlgebraObject
	DistributableLinearAlgebraObject ()
	Default constructor - create a distribution. More...

	DistributableLinearAlgebraObject (const DistributableLinearAlgebraObject &matrix)=delete
	Broken copy constructor. More...

void	operator= (const DistributableLinearAlgebraObject &)=delete
	Broken assignment operator. More...

virtual	~DistributableLinearAlgebraObject ()
	Destructor. More...

LinearAlgebraDistribution *	distribution_pt () const
	access to the LinearAlgebraDistribution More...

unsigned	nrow () const
	access function to the number of global rows. More...

unsigned	nrow_local () const
	access function for the num of local rows on this processor. More...

unsigned	nrow_local (const unsigned &p) const
	access function for the num of local rows on this processor. More...

unsigned	first_row () const
	access function for the first row on this processor More...

unsigned	first_row (const unsigned &p) const
	access function for the first row on this processor More...

bool	distributed () const
	distribution is serial or distributed More...

bool	distribution_built () const

void	build_distribution (const LinearAlgebraDistribution *const dist_pt)

void	build_distribution (const LinearAlgebraDistribution &dist)

Private Attributes
Vector< double >	Inv_diag
	Vector of inverse diagonal entries. More...

Additional Inherited Members
Protected Member Functions inherited from oomph::DistributableLinearAlgebraObject
void	clear_distribution ()

Protected Attributes inherited from oomph::Preconditioner
bool	Silent_preconditioner_setup
	Boolean to indicate whether or not the build should be done silently. More...

std::ostream *	Stream_pt
	Pointer to the output stream – defaults to std::cout. More...

Detailed Description

Matrix-based diagonal preconditioner.

Constructor & Destructor Documentation

◆ MatrixBasedDiagPreconditioner() [1/2]

oomph::MatrixBasedDiagPreconditioner::MatrixBasedDiagPreconditioner ( )

inline

Constructor (empty)

52 {};

◆ ~MatrixBasedDiagPreconditioner()

oomph::MatrixBasedDiagPreconditioner::~MatrixBasedDiagPreconditioner ( )

inline

Destructor (empty)

55 {};

◆ MatrixBasedDiagPreconditioner() [2/2]

oomph::MatrixBasedDiagPreconditioner::MatrixBasedDiagPreconditioner ( const MatrixBasedDiagPreconditioner & )

delete

Broken copy constructor.

Member Function Documentation

◆ operator=()

void oomph::MatrixBasedDiagPreconditioner::operator= ( const MatrixBasedDiagPreconditioner & )

delete

Broken assignment operator.

◆ preconditioner_solve()

void oomph::MatrixBasedDiagPreconditioner::preconditioner_solve	(	const DoubleVector &	r,
		DoubleVector &	z
	)

virtual

Apply preconditioner to z, i.e. z=D^-1.

Apply preconditioner: Multiply r by the inverse of the diagonal.

Implements oomph::Preconditioner.

   {
 #ifdef PARANOID
     if (*r.distribution_pt() != *this->distribution_pt())
     {
       std::ostringstream error_message_stream;
       error_message_stream
         << "The r vector must have the same distribution as the "
            "preconditioner. "
         << "(this is the same as the matrix passed to setup())";
       throw OomphLibError(error_message_stream.str(),
                           OOMPH_CURRENT_FUNCTION,
                           OOMPH_EXCEPTION_LOCATION);
     }
     if (z.built())
     {
       if (*z.distribution_pt() != *this->distribution_pt())
       {
         std::ostringstream error_message_stream;
         error_message_stream
           << "The z vector distribution has been setup; it must have the "
           << "same distribution as the r vector (and preconditioner).";
         throw OomphLibError(error_message_stream.str(),
                             OOMPH_CURRENT_FUNCTION,
                             OOMPH_EXCEPTION_LOCATION);
       }
     }
 #endif
  
     // if z has not been setup then rebuild it
     if (!z.built())
     {
       z.build(this->distribution_pt(), 0.0);
     }
  
     // apply the preconditioner
     const double* r_values = r.values_pt();
     double* z_values = z.values_pt();
     unsigned nrow_local = this->nrow_local();
     for (unsigned i = 0; i < nrow_local; i++)
     {
       z_values[i] = Inv_diag[i] * r_values[i];
     }
   }

References oomph::DoubleVector::build(), oomph::DoubleVector::built(), oomph::DistributableLinearAlgebraObject::distribution_pt(), i, Inv_diag, oomph::DistributableLinearAlgebraObject::nrow_local(), OOMPH_CURRENT_FUNCTION, OOMPH_EXCEPTION_LOCATION, UniformPSDSelfTest::r, and oomph::DoubleVector::values_pt().

◆ setup()

void oomph::MatrixBasedDiagPreconditioner::setup ( )

virtual

Setup the preconditioner (store diagonal) from the fully assembled matrix.

Setup diagonal preconditioner: Store the inverse of the diagonal entries from the fully assembled matrix.

Implements oomph::Preconditioner.

   {
     // first attempt to cast to DistributableLinearAlgebraObject
     DistributableLinearAlgebraObject* dist_matrix_pt =
       dynamic_cast<DistributableLinearAlgebraObject*>(matrix_pt());
  
     // if it is a distributable matrix
     if (dist_matrix_pt != 0)
     {
       // cache the number of first_rows and nrow_local
       unsigned nrow_local = dist_matrix_pt->nrow_local();
       unsigned first_row = dist_matrix_pt->first_row();
  
       // resize the inverse diagonal storage
       Inv_diag.resize(nrow_local);
  
       // Extract the diagonal entries
       for (unsigned i = 0; i < nrow_local; i++)
       {
         unsigned index = i + first_row;
 #ifdef PARANOID
         if ((*matrix_pt())(i, index) == 0.0)
         {
           throw OomphLibError(
             "Zero diagonal in matrix --> Cannot use diagonal preconditioner.",
             OOMPH_CURRENT_FUNCTION,
             OOMPH_EXCEPTION_LOCATION);
         }
 #endif
         Inv_diag[i] = 1.0 / (*matrix_pt())(i, index);
       }
  
       // store the distribution
       this->build_distribution(dist_matrix_pt->distribution_pt());
     }
  
     // else it is not a distributable matrix
     else
     {
       // # of rows in the matrix
       unsigned n_row = matrix_pt()->nrow();
  
       // Resize the Inv_diag vector to accommodate the # of
       // diagonal entries
       Inv_diag.resize(n_row);
  
       // Extract the diagonal entries
       for (unsigned i = 0; i < n_row; i++)
       {
 #ifdef PARANOID
         if ((*matrix_pt())(i, i) == 0.0)
         {
           throw OomphLibError(
             "Zero diagonal in matrix --> Cannot use diagonal preconditioner.",
             OOMPH_CURRENT_FUNCTION,
             OOMPH_EXCEPTION_LOCATION);
         }
         else
 #endif
         {
           Inv_diag[i] = 1.0 / (*matrix_pt())(i, i);
         }
       }
  
       // create the distribution
       LinearAlgebraDistribution dist(comm_pt(), n_row, false);
       this->build_distribution(dist);
     }
   }

References oomph::DistributableLinearAlgebraObject::build_distribution(), oomph::DistributableLinearAlgebraObject::distribution_pt(), oomph::DistributableLinearAlgebraObject::first_row(), i, Inv_diag, oomph::Preconditioner::matrix_pt(), oomph::DoubleMatrixBase::nrow(), oomph::DistributableLinearAlgebraObject::nrow_local(), OOMPH_CURRENT_FUNCTION, and OOMPH_EXCEPTION_LOCATION.

Member Data Documentation

◆ Inv_diag

Vector<double> oomph::MatrixBasedDiagPreconditioner::Inv_diag

private

Vector of inverse diagonal entries.

Referenced by preconditioner_solve(), and setup().

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

Public Member Functions

Private Attributes

Additional Inherited Members