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Ifpack_Condest.cpp
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42 
43 #include "Ifpack_ConfigDefs.h"
44 #include "Ifpack_Condest.h"
45 #include "Ifpack_CondestType.h"
46 #include "Ifpack_Preconditioner.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
66  Epetra_Vector Ones(IFP.OperatorDomainMap());
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();
88  Epetra_LinearProblem Problem;
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 
108  Epetra_Vector LHS(IFP.OperatorDomainMap());
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 }
void SetLHS(Epetra_MultiVector *X)
void SetOperator(Epetra_RowMatrix *A)
virtual const Epetra_RowMatrix & Matrix() const =0
Returns a pointer to the matrix to be preconditioned.
virtual const Epetra_Map & OperatorDomainMap() const =0
static bool Solver
Definition: performance.cpp:70
Ifpack_CondestType
Ifpack_CondestType: enum to define the type of condition number estimate.
virtual const Epetra_Map & OperatorRangeMap() const =0
Uses AztecOO's GMRES.
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.
Uses AztecOO's CG.
double Ifpack_Condest(const Ifpack_Preconditioner &IFP, const Ifpack_CondestType CT, const int MaxIters, const double Tol, Epetra_RowMatrix *Matrix)
void SetRHS(Epetra_MultiVector *B)
cheap estimate
#define IFPACK_CHK_ERR(ifpack_err)
#define RHS(a)
Definition: MatGenFD.c:60