Ifpack Package Browser (Single Doxygen Collection)  Development
 All Classes Namespaces Files Functions Variables Typedefs Enumerations Enumerator Friends Macros Groups Pages
Ifpack_ex_ICT.cpp
Go to the documentation of this file.
1 //@HEADER
2 // ***********************************************************************
3 //
4 // Ifpack: Object-Oriented Algebraic Preconditioner Package
5 // Copyright (2002) Sandia Corporation
6 //
7 // Under terms of Contract DE-AC04-94AL85000, there is a non-exclusive
8 // license for use of this work by or on behalf of the U.S. Government.
9 //
10 // Redistribution and use in source and binary forms, with or without
11 // modification, are permitted provided that the following conditions are
12 // met:
13 //
14 // 1. Redistributions of source code must retain the above copyright
15 // notice, this list of conditions and the following disclaimer.
16 //
17 // 2. Redistributions in binary form must reproduce the above copyright
18 // notice, this list of conditions and the following disclaimer in the
19 // documentation and/or other materials provided with the distribution.
20 //
21 // 3. Neither the name of the Corporation nor the names of the
22 // contributors may be used to endorse or promote products derived from
23 // this software without specific prior written permission.
24 //
25 // THIS SOFTWARE IS PROVIDED BY SANDIA CORPORATION "AS IS" AND ANY
26 // EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
27 // IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
28 // PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL SANDIA CORPORATION OR THE
29 // CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
30 // EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
31 // PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
32 // PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
33 // LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
34 // NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
35 // SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
36 //
37 // Questions? Contact Michael A. Heroux (maherou@sandia.gov)
38 //
39 // ***********************************************************************
40 //@HEADER
41 
42 #include "Ifpack_ConfigDefs.h"
43 
44 #ifdef HAVE_MPI
45 #include "Epetra_MpiComm.h"
46 #else
47 #include "Epetra_SerialComm.h"
48 #endif
49 #include "Epetra_CrsMatrix.h"
50 #include "Epetra_MultiVector.h"
51 #include "Epetra_LinearProblem.h"
52 #include "Epetra_Time.h"
53 #include "Galeri_Maps.h"
54 #include "Galeri_CrsMatrices.h"
55 #include "Teuchos_ParameterList.hpp"
56 #include "Teuchos_RefCountPtr.hpp"
57 #include "AztecOO.h"
58 #include "Ifpack_AdditiveSchwarz.h"
59 #include "Ifpack_ICT.h"
60 
61 int main(int argc, char *argv[])
62 {
63 
64  // initialize MPI and Epetra communicator
65 #ifdef HAVE_MPI
66  MPI_Init(&argc,&argv);
67  Epetra_MpiComm Comm( MPI_COMM_WORLD );
68 #else
69  Epetra_SerialComm Comm;
70 #endif
71 
72  Teuchos::ParameterList GaleriList;
73 
74  // The problem is defined on a 2D grid, global size is nx * nx.
75  int nx = 30;
76  GaleriList.set("nx", nx);
77  GaleriList.set("ny", nx * Comm.NumProc());
78  GaleriList.set("mx", 1);
79  GaleriList.set("my", Comm.NumProc());
80  Teuchos::RefCountPtr<Epetra_Map> Map = Teuchos::rcp( Galeri::CreateMap("Cartesian2D", Comm, GaleriList) );
81  Teuchos::RefCountPtr<Epetra_RowMatrix> A = Teuchos::rcp( Galeri::CreateCrsMatrix("Laplace2D", &*Map, GaleriList) );
82 
83  // =============================================================== //
84  // B E G I N N I N G O F I F P A C K C O N S T R U C T I O N //
85  // =============================================================== //
86 
88 
89  // builds an Ifpack_AdditiveSchwarz. This is templated with
90  // the local solvers, in this case Ifpack_ICT. Note that any
91  // other Ifpack_Preconditioner-derived class can be used
92  // instead of Ifpack_ICT.
93 
94  // In this example the overlap is zero. Use
95  // Prec(A,OverlapLevel) for the general case.
97 
98  // `1.0' means that the factorization should approximatively
99  // keep the same number of nonzeros per row of the original matrix.
100  List.set("fact: ict level-of-fill", 1.0);
101  // no modifications on the diagonal
102  List.set("fact: absolute threshold", 0.0);
103  List.set("fact: relative threshold", 1.0);
104  List.set("fact: relaxation value", 0.0);
105  // matrix `laplace_2d_bc' is not symmetric because of the way
106  // boundary conditions are imposed. We can filter the singletons,
107  // (that is, Dirichlet nodes) and end up with a symmetric
108  // matrix (as ICT requires).
109  List.set("schwarz: filter singletons", true);
110 
111  // sets the parameters
112  IFPACK_CHK_ERR(Prec.SetParameters(List));
113 
114  // initialize the preconditioner. At this point the matrix must
115  // have been FillComplete()'d, but actual values are ignored.
116  IFPACK_CHK_ERR(Prec.Initialize());
117 
118  // Builds the preconditioners, by looking for the values of
119  // the matrix.
120  IFPACK_CHK_ERR(Prec.Compute());
121 
122  // =================================================== //
123  // E N D O F I F P A C K C O N S T R U C T I O N //
124  // =================================================== //
125 
126  // At this point, we need some additional objects
127  // to define and solve the linear system.
128 
129  // defines LHS and RHS
130  Epetra_Vector LHS(A->OperatorDomainMap());
131  Epetra_Vector RHS(A->OperatorDomainMap());
132 
133  LHS.PutScalar(0.0);
134  RHS.Random();
135 
136  // need an Epetra_LinearProblem to define AztecOO solver
137  Epetra_LinearProblem Problem(&*A,&LHS,&RHS);
138 
139  // now we can allocate the AztecOO solver
140  AztecOO Solver(Problem);
141 
142  // specify solver
143  Solver.SetAztecOption(AZ_solver,AZ_cg_condnum);
144  Solver.SetAztecOption(AZ_output,32);
145 
146  // HERE WE SET THE IFPACK PRECONDITIONER
147  Solver.SetPrecOperator(&Prec);
148 
149  // .. and here we solve
150  // NOTE: with one process, the solver must converge in
151  // one iteration.
152  Solver.Iterate(1550,1e-5);
153 
154  // Prints out some information about the preconditioner
155  std::cout << Prec;
156 
157 #ifdef HAVE_MPI
158  MPI_Finalize();
159 #endif
160 
161  return (EXIT_SUCCESS);
162 }
ParameterList & set(std::string const &name, T &&value, std::string const &docString="", RCP< const ParameterEntryValidator > const &validator=null)
static bool Solver
Definition: performance.cpp:70
virtual int Initialize()
Initialized the preconditioner.
TEUCHOS_DEPRECATED RCP< T > rcp(T *p, Dealloc_T dealloc, bool owns_mem)
Ifpack_AdditiveSchwarz: a class to define Additive Schwarz preconditioners of Epetra_RowMatrix&#39;s.
int main(int argc, char *argv[])
int NumProc() const
virtual int SetParameters(Teuchos::ParameterList &List)
Sets the parameters.
virtual int Compute()
Computes the preconditioner.
#define IFPACK_CHK_ERR(ifpack_err)
#define RHS(a)
Definition: MatGenFD.c:60