Amesos_Component: A pure virtual class for direct solvers to be used within Amesos_Merikos to form a parallel direct solver. More...

#include <Amesos_Component.h>

Public Member Functions

virtual	~Amesos_Component ()
	Destructor.

virtual int	PartialFactorization ()=0
	Performs partial factorization on the matrix A.
virtual int	Lsolve ()=0
	Solves L X = B (or L^T x = B)
virtual int	Usolve ()=0
	Solves L X = B (or L^T x = B)

virtual int	SetRowPermutation (int *RowPermutation)=0
	SetRowPermutation.
virtual int	SetColumnPermutation (int *ColumnPermutation)=0
	SetColumnPermutation.
virtual int	SetSubMatrixSize (int SubMatrixSize)=0
	SetSubMatrixSize.
virtual int	GetRowPermutation (int **RowPermutation)=0
	GetRowPermutation.
virtual int	GetColumnPermutation (int **ColumnPermutation)=0
	GetColumnPermutation.
virtual int	GetSubMatrixSize (int *SubMatrixSize)=0
	GetSubMatrixSize.
virtual int	GetSchurComplement (Epetra_CrsMatrix *SchurComplement)=0
	GetSchurComplement.

Detailed Description

Amesos_Component: A pure virtual class for direct solvers to be used within Amesos_Merikos to form a parallel direct solver.

The Amesos_Component interface specifies what Amesos_Merikos needs. Any Amesos class that implements Amesos_Component can be used by Amesos_Merikos to perform partial solves on subblocks of the matrix.

Member functions added by Amesos_Component.

PartialFactorization()
- PartialFactorization performs factors at most the first SubMatrixSize_ rows and columns.
- PartialFactorization delays the factorization of any columns which generate unstable (i.e. too small) pivots.
- PartialFactorization computes and returns the schur complement.
- PartialFactorization does not need a symbolic factorization phase. It uses the permutation given by SetRowPermutation.
Lsolve performs a raw partial solve, treating the unfactored rows and columns as the identity without row or column permutation.
Usolve performs a raw partial solve, treating the unfactored rows and columns as the identity without row or column permutation.
SetRowPermutation - sets the row permutation
GetRowPermutation - gets the row permutation
SetColumnPermutation - sets the column permutation
GetColumnPermutation - gets the column permutation
SetSubMatrixSize - Sets the maximum number of rows (and columns) to factor.
GetSubMatrixSize - Returns the number of rows (and columns) actually factored.
SchurComplement - Returns the Schur complement, i.e. L21(SubMatrixSize+1:MatrixSize,1:SubMatrixSize) * U12(1:SubMatrixSize,SubMatrixSize+1:MatrixSize)

Usage Examples

Basic calling sequence

    Epetra_LinearProblem Problem(A,X,B);
    Amesos_SolverName Solver(Problem);

    Solver.PartialFactorization() ; 
      ... Ancestor factorization
    Solver.Lsolve() ; 
      ... Ancestor solves
    Solver.Usolve() ;

Preconditions: An ordering Postconditions: Constructor requirements

Every Amesos_SolverName class should accept an Epetra_LinearProblem

Member Function Documentation

virtual int Amesos_Component::GetColumnPermutation ( int ** ColumnPermutation ) [pure virtual]

GetColumnPermutation.

ColumnPermutation reflects any row permutations performed by PartialFactorization(). Note: It is not yet clear whether this row permutation includes the ColumnPermuation upon input or whether it returns only the row permuations performed by the most recent call to PartialFactorization(). In other words, in the absence of pivoting, ColumnPermutation might be identical to that given by SetColumnPermutation() or it might be the identity permutation.

virtual int Amesos_Component::GetRowPermutation ( int ** RowPermutation ) [pure virtual]

GetRowPermutation.

RowPermutation reflects any row permutations performed by PartialFactorization(). Note: It is not yet clear whether this row permutation includes the RowPermuation upon input or whether it returns only the row permuations performed by the most recent call to PartialFactorization(). In other words, in the absence of pivoting, RowPermutation might be identical to that given by SetRowPermutation() or it might be the identity permutation.

virtual int Amesos_Component::Lsolve ( ) [pure virtual]

Solves L X = B (or L^T x = B)

Returns:: Integer error code, set to 0 if successful.

virtual int Amesos_Component::PartialFactorization ( ) [pure virtual]

Performs partial factorization on the matrix A.

Partial Factorization perfom

Returns:: Integer error code, set to 0 if successful.

virtual int Amesos_Component::Usolve ( ) [pure virtual]