//=============================================================================
int Ifpack_CrsIct::Condest(bool Trans, double & ConditionNumberEstimate) const {
if (Condest_>=0.0) {
ConditionNumberEstimate = Condest_;
return(0);
}
// Create a vector with all values equal to one
Epetra_Vector Ones(A_.RowMap());
Epetra_Vector OnesResult(Ones);
Ones.PutScalar(1.0);
EPETRA_CHK_ERR(Solve(Trans, Ones, OnesResult)); // Compute the effect of the solve on the vector of ones
EPETRA_CHK_ERR(OnesResult.Abs(OnesResult)); // Make all values non-negative
EPETRA_CHK_ERR(OnesResult.MaxValue(&ConditionNumberEstimate)); // Get the maximum value across all processors
Condest_ = ConditionNumberEstimate; // Save value for possible later calls
return(0);
}
double Ifpack_Condest(const Ifpack_Preconditioner& IFP,
const Ifpack_CondestType CT,
const int MaxIters,
const double Tol,
Epetra_RowMatrix* Matrix)
{
double ConditionNumberEstimate = -1.0;
if (CT == Ifpack_Cheap) {
// Create a vector with all values equal to one
Epetra_Vector Ones(IFP.OperatorDomainMap());
Ones.PutScalar(1.0);
// Create the vector of results
Epetra_Vector OnesResult(IFP.OperatorRangeMap());
// Compute the effect of the solve on the vector of ones
IFPACK_CHK_ERR(IFP.ApplyInverse(Ones, OnesResult));
// Make all values non-negative
IFPACK_CHK_ERR(OnesResult.Abs(OnesResult));
// Get the maximum value across all processors
IFPACK_CHK_ERR(OnesResult.MaxValue(&ConditionNumberEstimate));
}
else if (CT == Ifpack_CG) {
#ifdef HAVE_IFPACK_AZTECOO
if (Matrix == 0)
Matrix = (Epetra_RowMatrix*)&(IFP.Matrix());
Epetra_Vector LHS(IFP.OperatorDomainMap());
LHS.PutScalar(0.0);
Epetra_Vector RHS(IFP.OperatorRangeMap());
RHS.Random();
Epetra_LinearProblem Problem;
Problem.SetOperator(Matrix);
Problem.SetLHS(&LHS);
Problem.SetRHS(&RHS);
AztecOO Solver(Problem);
Solver.SetAztecOption(AZ_output,AZ_none);
Solver.SetAztecOption(AZ_solver,AZ_cg_condnum);
Solver.Iterate(MaxIters,Tol);
const double* status = Solver.GetAztecStatus();
ConditionNumberEstimate = status[AZ_condnum];
#endif
} else if (CT == Ifpack_GMRES) {
#ifdef HAVE_IFPACK_AZTECOO
if (Matrix == 0)
Matrix = (Epetra_RowMatrix*)&(IFP.Matrix());
Epetra_Vector LHS(IFP.OperatorDomainMap());
LHS.PutScalar(0.0);
Epetra_Vector RHS(IFP.OperatorRangeMap());
RHS.Random();
Epetra_LinearProblem Problem;
Problem.SetOperator(Matrix);
Problem.SetLHS(&LHS);
Problem.SetRHS(&RHS);
AztecOO Solver(Problem);
Solver.SetAztecOption(AZ_solver,AZ_gmres_condnum);
Solver.SetAztecOption(AZ_output,AZ_none);
// the following can be problematic for large problems,
// but any restart would destroy useful information about
// the condition number.
Solver.SetAztecOption(AZ_kspace,MaxIters);
Solver.Iterate(MaxIters,Tol);
const double* status = Solver.GetAztecStatus();
ConditionNumberEstimate = status[AZ_condnum];
#endif
}
return(ConditionNumberEstimate);
}
