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// ---------------------------------------------------------------------
//
// Copyright (C) 2005 - 2015 by the deal.II authors
//
// This file is part of the deal.II library.
//
// The deal.II library is free software; you can use it, redistribute
// it, and/or modify it under the terms of the GNU Lesser General
// Public License as published by the Free Software Foundation; either
// version 2.1 of the License, or (at your option) any later version.
// The full text of the license can be found in the file LICENSE at
// the top level of the deal.II distribution.
//
// ---------------------------------------------------------------------
// See documentation of BlockMatrixArray for documentation of this example
#include <deal.II/base/logstream.h>
#include <deal.II/lac/block_matrix_array.h>
#include <deal.II/lac/full_matrix.h>
#include <deal.II/lac/vector.h>
#include <deal.II/lac/block_vector.h>
#include <deal.II/lac/precondition.h>
#include <deal.II/lac/solver_cg.h>
#include <deal.II/lac/solver_gmres.h>
#include <iostream>
#include <fstream>
using namespace dealii;
double Adata[] =
{
4., .5, .1, 0.,
.5, 4., .5, .1,
.1, .5, 4., .5,
0., .1, .5, 4.
};
double B1data[] =
{
.5, .1,
.4, .2,
.3, .3,
.2, .4
};
double B2data[] =
{
.3, 0., -.3, 0.,
-.3, 0., .3, 0.
};
double Cdata[] =
{
8., 1.,
1., 8.
};
int main ()
{
FullMatrix<float> A(4,4);
FullMatrix<float> B1(4,2);
FullMatrix<float> B2(2,4);
FullMatrix<float> C(2,2);
A.fill(Adata);
B1.fill(B1data);
B2.fill(B2data);
C.fill(Cdata);
BlockMatrixArray<double> matrix(2, 2);
matrix.enter(A,0,0,2.);
matrix.enter(B1,0,1,-1.);
matrix.enter(B2,0,1,1., true);
matrix.enter(B2,1,0,1.);
matrix.enter(B1,1,0,-1., true);
matrix.enter(C,1,1);
matrix.print_latex(deallog);
std::vector<unsigned int> block_sizes(2);
block_sizes[0] = 4;
block_sizes[1] = 2;
BlockVector<double> result(block_sizes);
BlockVector<double> x(block_sizes);
BlockVector<double> y(block_sizes);
for (unsigned int i=0; i<result.size(); ++i)
result(i) = i;
matrix.vmult(y, result);
SolverControl control(100,1.e-10);
PreconditionIdentity id;
SolverCG<BlockVector<double> > cg(control);
cg.solve(matrix, x, y, id);
x.add(-1., result);
deallog << "Error " << x.l2_norm() << std::endl;
deallog << "Error A-norm "
<< std::sqrt(matrix.matrix_norm_square(x))
<< std::endl;
FullMatrix<float> Ainv(4,4);
Ainv.invert(A);
FullMatrix<float> Cinv(2,2);
Cinv.invert(C);
BlockTrianglePrecondition<double>
precondition(2);
precondition.enter(Ainv,0,0,.5);
precondition.enter(Cinv,1,1);
cg.solve(matrix, x, y, precondition);
x.add(-1., result);
deallog << "Error " << x.l2_norm() << std::endl;
precondition.enter(B1,1,0,-1., true);
precondition.enter(B2,1,0,1.);
SolverGMRES<BlockVector<double> > gmres(control);
gmres.solve(matrix, x, y, precondition);
x.add(-1., result);
deallog << "Error " << x.l2_norm() << std::endl;
return 0;
}
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