Ifpack_Condest.cpp

00001 /*@HEADER
00002 // ***********************************************************************
00003 //
00004 //       Ifpack: Object-Oriented Algebraic Preconditioner Package
00005 //                 Copyright (2002) Sandia Corporation
00006 //
00007 // Under terms of Contract DE-AC04-94AL85000, there is a non-exclusive
00008 // license for use of this work by or on behalf of the U.S. Government.
00009 //
00010 // This library is free software; you can redistribute it and/or modify
00011 // it under the terms of the GNU Lesser General Public License as
00012 // published by the Free Software Foundation; either version 2.1 of the
00013 // License, or (at your option) any later version.
00014 //
00015 // This library is distributed in the hope that it will be useful, but
00016 // WITHOUT ANY WARRANTY; without even the implied warranty of
00017 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00018 // Lesser General Public License for more details.
00019 //
00020 // You should have received a copy of the GNU Lesser General Public
00021 // License along with this library; if not, write to the Free Software
00022 // Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
00023 // USA
00024 // Questions? Contact Michael A. Heroux (maherou@sandia.gov)
00025 //
00026 // ***********************************************************************
00027 //@HEADER
00028 */
00029 
00030 #include "Ifpack_ConfigDefs.h"
00031 #include "Ifpack_Condest.h"
00032 #include "Ifpack_CondestType.h"
00033 #include "Ifpack_Preconditioner.h"
00034 #include "Epetra_Vector.h"
00035 #include "Epetra_LinearProblem.h"
00036 #include "Epetra_Map.h"
00037 #include "Epetra_RowMatrix.h"
00038 #ifdef HAVE_IFPACK_AZTECOO
00039 #include "AztecOO.h"
00040 #endif
00041 
00042 double Ifpack_Condest(const Ifpack_Preconditioner& IFP,
00043               const Ifpack_CondestType CT,
00044               const int MaxIters,
00045               const double Tol,
00046               Epetra_RowMatrix* Matrix)
00047 {
00048   double ConditionNumberEstimate = -1.0;
00049 
00050   if (CT == Ifpack_Cheap) {
00051 
00052     // Create a vector with all values equal to one
00053     Epetra_Vector Ones(IFP.OperatorDomainMap());
00054     Ones.PutScalar(1.0);
00055     // Create the vector of results
00056     Epetra_Vector OnesResult(IFP.OperatorRangeMap());
00057     // Compute the effect of the solve on the vector of ones
00058     IFPACK_CHK_ERR(IFP.ApplyInverse(Ones, OnesResult)); 
00059     // Make all values non-negative
00060     IFPACK_CHK_ERR(OnesResult.Abs(OnesResult)); 
00061     // Get the maximum value across all processors
00062     IFPACK_CHK_ERR(OnesResult.MaxValue(&ConditionNumberEstimate)); 
00063 
00064   }
00065   else if (CT == Ifpack_CG) {
00066 
00067 #ifdef HAVE_IFPACK_AZTECOO
00068     if (Matrix == 0)
00069       Matrix = (Epetra_RowMatrix*)&(IFP.Matrix());
00070 
00071     Epetra_Vector LHS(IFP.OperatorDomainMap());
00072     LHS.PutScalar(0.0);
00073     Epetra_Vector RHS(IFP.OperatorRangeMap());
00074     RHS.Random();
00075     Epetra_LinearProblem Problem;
00076     Problem.SetOperator(Matrix);
00077     Problem.SetLHS(&LHS);
00078     Problem.SetRHS(&RHS);
00079 
00080     AztecOO Solver(Problem);
00081     Solver.SetAztecOption(AZ_output,AZ_none);
00082     Solver.SetAztecOption(AZ_solver,AZ_cg_condnum);
00083     Solver.Iterate(MaxIters,Tol);
00084 
00085     const double* status = Solver.GetAztecStatus();
00086     ConditionNumberEstimate = status[AZ_condnum];
00087 #endif
00088 
00089   } else if (CT == Ifpack_GMRES) {
00090 
00091 #ifdef HAVE_IFPACK_AZTECOO
00092     if (Matrix == 0)
00093       Matrix = (Epetra_RowMatrix*)&(IFP.Matrix());
00094 
00095     Epetra_Vector LHS(IFP.OperatorDomainMap());
00096     LHS.PutScalar(0.0);
00097     Epetra_Vector RHS(IFP.OperatorRangeMap());
00098     RHS.Random();
00099     Epetra_LinearProblem Problem;
00100     Problem.SetOperator(Matrix);
00101     Problem.SetLHS(&LHS);
00102     Problem.SetRHS(&RHS);
00103 
00104     AztecOO Solver(Problem);
00105     Solver.SetAztecOption(AZ_solver,AZ_gmres_condnum);
00106     Solver.SetAztecOption(AZ_output,AZ_none);
00107     // the following can be problematic for large problems,
00108     // but any restart would destroy useful information about
00109     // the condition number.
00110     Solver.SetAztecOption(AZ_kspace,MaxIters);
00111     Solver.Iterate(MaxIters,Tol);
00112 
00113     const double* status = Solver.GetAztecStatus();
00114     ConditionNumberEstimate = status[AZ_condnum];
00115 #endif
00116   }
00117 
00118   return(ConditionNumberEstimate);
00119 
00120 }

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