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Ifpack_LocalFilter Class Reference

Ifpack_LocalFilter a class for light-weight extraction of the submatrix corresponding to local rows and columns. More...

#include <Ifpack_LocalFilter.h>

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## Public Member Functions

int SetOwnership (bool)
Sets ownership.

int SetUseTranspose (bool UseTranspose_in)
Sets use transpose (not implemented).

bool UseTranspose () const
Returns the current UseTranspose setting.

bool HasNormInf () const
Returns true if the this object can provide an approximate Inf-norm, false otherwise.

const Epetra_CommComm () const
Returns a pointer to the Epetra_Comm communicator associated with this operator.

const Epetra_MapOperatorDomainMap () const
Returns the Epetra_Map object associated with the domain of this operator.

const Epetra_MapOperatorRangeMap () const
Returns the Epetra_Map object associated with the range of this operator.

const Epetra_BlockMapMap () const

const char * Label () const

Ifpack_LocalFilter (const Teuchos::RefCountPtr< const Epetra_RowMatrix > &Matrix)
Constructor.

virtual ~Ifpack_LocalFilter ()
Destructor.

virtual int NumMyRowEntries (int MyRow, int &NumEntries) const
Returns the number of nonzero entries in MyRow. More...

virtual int MaxNumEntries () const
Returns the maximum of NumMyRowEntries() over all rows.

virtual int ExtractMyRowCopy (int MyRow, int Length, int &NumEntries, double *Values, int *Indices) const
Returns a copy of the specified local row in user-provided arrays. More...

virtual int ExtractDiagonalCopy (Epetra_Vector &Diagonal) const
Returns a copy of the main diagonal in a user-provided vector. More...

virtual int Multiply (bool TransA, const Epetra_MultiVector &X, Epetra_MultiVector &Y) const
Returns the result of a Epetra_RowMatrix multiplied by a Epetra_MultiVector X in Y. More...

virtual int Solve (bool, bool, bool, const Epetra_MultiVector &, Epetra_MultiVector &) const
Returns result of a local-only solve using a triangular Epetra_RowMatrix with Epetra_MultiVectors X and Y (NOT IMPLEMENTED).

virtual int Apply (const Epetra_MultiVector &X, Epetra_MultiVector &Y) const

virtual int ApplyInverse (const Epetra_MultiVector &X, Epetra_MultiVector &Y) const

virtual int InvRowSums (Epetra_Vector &) const
Computes the sum of absolute values of the rows of the Epetra_RowMatrix, results returned in x (NOT IMPLEMENTED).

virtual int LeftScale (const Epetra_Vector &)
Scales the Epetra_RowMatrix on the left with a Epetra_Vector x (NOT IMPLEMENTED).

virtual int InvColSums (Epetra_Vector &) const
Computes the sum of absolute values of the columns of the Epetra_RowMatrix, results returned in x (NOT IMPLEMENTED).

virtual int RightScale (const Epetra_Vector &)
Scales the Epetra_RowMatrix on the right with a Epetra_Vector x (NOT IMPLEMENTED).

virtual bool Filled () const
If FillComplete() has been called, this query returns true, otherwise it returns false.

virtual double NormInf () const
Returns the infinity norm of the global matrix.

virtual double NormOne () const
Returns the one norm of the global matrix.

virtual int NumGlobalNonzeros () const
Returns the number of nonzero entries in the global matrix.

virtual int NumGlobalRows () const
Returns the number of global matrix rows.

virtual int NumGlobalCols () const
Returns the number of global matrix columns.

virtual int NumGlobalDiagonals () const
Returns the number of global nonzero diagonal entries, based on global row/column index comparisons.

virtual long long NumGlobalNonzeros64 () const
Returns the number of nonzero entries in the global matrix.

virtual long long NumGlobalRows64 () const
Returns the number of global matrix rows.

virtual long long NumGlobalCols64 () const
Returns the number of global matrix columns.

virtual long long NumGlobalDiagonals64 () const
Returns the number of global nonzero diagonal entries, based on global row/column index comparisons.

virtual int NumMyNonzeros () const
Returns the number of nonzero entries in the calling processor's portion of the matrix.

virtual int NumMyRows () const
Returns the number of matrix rows owned by the calling processor.

virtual int NumMyCols () const
Returns the number of matrix columns owned by the calling processor.

virtual int NumMyDiagonals () const
Returns the number of local nonzero diagonal entries, based on global row/column index comparisons.

virtual bool LowerTriangular () const
If matrix is lower triangular in local index space, this query returns true, otherwise it returns false.

virtual bool UpperTriangular () const
If matrix is upper triangular in local index space, this query returns true, otherwise it returns false.

virtual const Epetra_MapRowMatrixRowMap () const
Returns the Epetra_Map object associated with the rows of this matrix.

virtual const Epetra_MapRowMatrixColMap () const
Returns the Epetra_Map object associated with the columns of this matrix.

virtual const Epetra_ImportRowMatrixImporter () const
Returns the Epetra_Import object that contains the import operations for distributed operations.

## Detailed Description

Ifpack_LocalFilter a class for light-weight extraction of the submatrix corresponding to local rows and columns.

Class Ifpack_LocalFilter enables a light-weight contruction of an Epetra_RowMatrix-derived object, containing only the elements of the original, distributed matrix with local row and column ID. The local submatrix is based on a communicator containing the local process only. Each process will have its local object, corresponding to the local submatrix. Submatrices may or may not overlap.

The following instructions can be used to create "localized" matrices:

#include "Ifpack_LocalFilter.h"
...
Teuchos::RefCountPtr<Epetra_RowMatrix> A; // fill the elements of A,
A->FillComplete();

Once created, LocalA defined, on each process, the submatrix corresponding to local rows and columns only. The creation and use of LocalA is "cheap", as the elements of the local matrix are obtained through calls to ExtractMyRowCopy on the original, distributed matrix, say A. This means that A must remain in scope every time LocalA is accessed.

A very convenient use of this class is to use Ifpack solvers to compute the LU factorizations of local blocks. If applied to a localized matrix, several Ifpack objects can operator in the same phase in a safe way, without non-required data exchange.

Date
Sep-04

Definition at line 98 of file Ifpack_LocalFilter.h.

## Member Function Documentation

 int Ifpack_LocalFilter::ExtractDiagonalCopy ( Epetra_Vector & Diagonal ) const
virtual

Returns a copy of the main diagonal in a user-provided vector.

Parameters
 Diagonal - (Out) Extracted main diagonal.
Returns
Integer error code, set to 0 if successful.

Implements Epetra_RowMatrix.

Definition at line 167 of file Ifpack_LocalFilter.cpp.

 int Ifpack_LocalFilter::ExtractMyRowCopy ( int MyRow, int Length, int & NumEntries, double * Values, int * Indices ) const
virtual

Returns a copy of the specified local row in user-provided arrays.

Parameters
 MyRow - (In) Local row to extract. Length - (In) Length of Values and Indices. NumEntries - (Out) Number of nonzero entries extracted. Values - (Out) Extracted values for this row. Indices - (Out) Extracted global column indices for the corresponding values.
Returns
Integer error code, set to 0 if successful.

Implements Epetra_RowMatrix.

Definition at line 131 of file Ifpack_LocalFilter.cpp.

Referenced by Ifpack_LocalFilter().

 virtual int Ifpack_LocalFilter::Multiply ( bool TransA, const Epetra_MultiVector & X, Epetra_MultiVector & Y ) const
inlinevirtual

Returns the result of a Epetra_RowMatrix multiplied by a Epetra_MultiVector X in Y.

Parameters
 TransA -(In) If true, multiply by the transpose of matrix, otherwise just use matrix. X - (In) A Epetra_MultiVector of dimension NumVectors to multiply with matrix. Y -(Out) A Epetra_MultiVector of dimension NumVectorscontaining result.
Returns
Integer error code, set to 0 if successful.

Implements Epetra_RowMatrix.

Definition at line 175 of file Ifpack_LocalFilter.h.

 virtual int Ifpack_LocalFilter::NumMyRowEntries ( int MyRow, int & NumEntries ) const
inlinevirtual

Returns the number of nonzero entries in MyRow.

Parameters
 MyRow - (In) Local row. NumEntries - (Out) Number of nonzero values present.
Returns
Integer error code, set to 0 if successful.

Implements Epetra_RowMatrix.

Definition at line 123 of file Ifpack_LocalFilter.h.

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