/usr/include/dolfin/la/SingularSolver.h is in libdolfin1.0-dev 1.0.0-1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 | // Copyright (C) 2008-2011 Anders Logg
//
// This file is part of DOLFIN.
//
// DOLFIN is free software: you can 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 3 of the License, or
// (at your option) any later version.
//
// DOLFIN is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with DOLFIN. If not, see <http://www.gnu.org/licenses/>.
//
// First added: 2005-09-19
// Last changed: 2011-10-06
#ifndef __SINGULAR_SOLVER_H
#define __SINGULAR_SOLVER_H
#include <boost/scoped_ptr.hpp>
#include <dolfin/common/types.h>
#include <dolfin/common/Variable.h>
#include "LinearSolver.h"
namespace dolfin
{
/// This class provides a linear solver for singular linear systems
/// Ax = b where A has a one-dimensional null-space (kernel). This
/// may happen for example when solving Poisson's equation with
/// pure Neumann boundary conditions.
///
/// The solver attempts to create an extended non-singular system
/// by adding the constraint [1, 1, 1, ...]^T x = 0.
///
/// If an optional mass matrix M is supplied, the solver attempts
/// to create an extended non-singular system by adding the
/// constraint m^T x = 0 where m is the lumped mass matrix. This
/// corresponds to setting the average (integral) of the finite
/// element function with coefficients x to zero.
///
/// The solver makes not attempt to check that the null-space is
/// indeed one-dimensional. It is also assumed that the system
/// Ax = b retains its sparsity pattern between calls to solve().
class SingularSolver : public Variable
{
public:
/// Create linear solver
SingularSolver(std::string method = "lu",
std::string preconditioner = "ilu");
/// Destructor
~SingularSolver();
/// Solve linear system Ax = b
uint solve(const GenericMatrix& A, GenericVector& x, const GenericVector& b);
/// Solve linear system Ax = b using mass matrix M for setting constraint
uint solve(const GenericMatrix& A, GenericVector& x, const GenericVector& b,
const GenericMatrix& M);
/// Default parameter values
static Parameters default_parameters()
{
Parameters p("singular_solver");
p.add(LinearSolver::default_parameters());
return p;
}
private:
// Initialize extended system
void init(const GenericMatrix& A);
// Create extended system
void create(const GenericMatrix& A, const GenericVector& b, const GenericMatrix* M);
// Linear solver
LinearSolver linear_solver;
// Extended matrix
boost::scoped_ptr<GenericMatrix> B;
// Solution of extended system
boost::scoped_ptr<GenericVector> y;
// Extended vector
boost::scoped_ptr<GenericVector> c;
};
}
#endif
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