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Ifpack_Condest.cpp
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4// Ifpack: Object-Oriented Algebraic Preconditioner Package
5// Copyright (2002) Sandia Corporation
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42
43#include "Ifpack_ConfigDefs.h"
44#include "Ifpack_Condest.h"
45#include "Ifpack_CondestType.h"
47#include "Epetra_Vector.h"
48#include "Epetra_LinearProblem.h"
49#include "Epetra_Map.h"
50#include "Epetra_RowMatrix.h"
51#ifdef HAVE_IFPACK_AZTECOO
52#include "AztecOO.h"
53#endif
54
56 const Ifpack_CondestType CT,
57 const int MaxIters,
58 const double Tol,
59 Epetra_RowMatrix* Matrix)
60{
61 double ConditionNumberEstimate = -1.0;
62
63 if (CT == Ifpack_Cheap) {
64
65 // Create a vector with all values equal to one
67 Ones.PutScalar(1.0);
68 // Create the vector of results
69 Epetra_Vector OnesResult(IFP.OperatorRangeMap());
70 // Compute the effect of the solve on the vector of ones
71 IFPACK_CHK_ERR(IFP.ApplyInverse(Ones, OnesResult));
72 // Make all values non-negative
73 IFPACK_CHK_ERR(OnesResult.Abs(OnesResult));
74 // Get the maximum value across all processors
75 IFPACK_CHK_ERR(OnesResult.MaxValue(&ConditionNumberEstimate));
76
77 }
78 else if (CT == Ifpack_CG) {
79
80#ifdef HAVE_IFPACK_AZTECOO
81 if (Matrix == 0)
82 Matrix = (Epetra_RowMatrix*)&(IFP.Matrix());
83
85 LHS.PutScalar(0.0);
87 RHS.Random();
89 Problem.SetOperator(Matrix);
90 Problem.SetLHS(&LHS);
91 Problem.SetRHS(&RHS);
92
93 AztecOO Solver(Problem);
94 Solver.SetAztecOption(AZ_output,AZ_none);
95 Solver.SetAztecOption(AZ_solver,AZ_cg_condnum);
96 Solver.Iterate(MaxIters,Tol);
97
98 const double* status = Solver.GetAztecStatus();
99 ConditionNumberEstimate = status[AZ_condnum];
100#endif
101
102 } else if (CT == Ifpack_GMRES) {
103
104#ifdef HAVE_IFPACK_AZTECOO
105 if (Matrix == 0)
106 Matrix = (Epetra_RowMatrix*)&(IFP.Matrix());
107
109 LHS.PutScalar(0.0);
111 RHS.Random();
112 Epetra_LinearProblem Problem;
113 Problem.SetOperator(Matrix);
114 Problem.SetLHS(&LHS);
115 Problem.SetRHS(&RHS);
116
117 AztecOO Solver(Problem);
118 Solver.SetAztecOption(AZ_solver,AZ_gmres_condnum);
119 Solver.SetAztecOption(AZ_output,AZ_none);
120 // the following can be problematic for large problems,
121 // but any restart would destroy useful information about
122 // the condition number.
123 Solver.SetAztecOption(AZ_kspace,MaxIters);
124 Solver.Iterate(MaxIters,Tol);
125
126 const double* status = Solver.GetAztecStatus();
127 ConditionNumberEstimate = status[AZ_condnum];
128#endif
129 }
130
131 return(ConditionNumberEstimate);
132
133}
Solver
Ifpack_CondestType
Ifpack_CondestType: enum to define the type of condition number estimate.
@ Ifpack_Cheap
cheap estimate
@ Ifpack_GMRES
Uses AztecOO's GMRES.
@ Ifpack_CG
Uses AztecOO's CG.
double Ifpack_Condest(const Ifpack_Preconditioner &IFP, const Ifpack_CondestType CT, const int MaxIters, const double Tol, Epetra_RowMatrix *Matrix)
#define IFPACK_CHK_ERR(ifpack_err)
#define RHS(a)
Definition: MatGenFD.c:60
void SetOperator(Epetra_RowMatrix *A)
void SetRHS(Epetra_MultiVector *B)
void SetLHS(Epetra_MultiVector *X)
int Abs(const Epetra_MultiVector &A)
int MaxValue(double *Result) const
int PutScalar(double ScalarConstant)
virtual const Epetra_Map & OperatorDomainMap() const=0
virtual const Epetra_Map & OperatorRangeMap() const=0
Ifpack_Preconditioner: basic class for preconditioning in Ifpack.
virtual int ApplyInverse(const Epetra_MultiVector &X, Epetra_MultiVector &Y) const =0
Applies the preconditioner to vector X, returns the result in Y.
virtual const Epetra_RowMatrix & Matrix() const =0
Returns a pointer to the matrix to be preconditioned.