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/*
* LinearSystem class wraps some gsl routines for solving linear systems
*
* Authors:
* Marco Cecchetti <mrcekets at gmail.com>
*
* Copyright 2008 authors
*
* This library is free software; you can redistribute it and/or
* modify it either under the terms of the GNU Lesser General Public
* License version 2.1 as published by the Free Software Foundation
* (the "LGPL") or, at your option, under the terms of the Mozilla
* Public License Version 1.1 (the "MPL"). If you do not alter this
* notice, a recipient may use your version of this file under either
* the MPL or the LGPL.
*
* You should have received a copy of the LGPL along with this library
* in the file COPYING-LGPL-2.1; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
* You should have received a copy of the MPL along with this library
* in the file COPYING-MPL-1.1
*
* The contents of this file are subject to the Mozilla Public License
* Version 1.1 (the "License"); you may not use this file except in
* compliance with the License. You may obtain a copy of the License at
* http://www.mozilla.org/MPL/
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY
* OF ANY KIND, either express or implied. See the LGPL or the MPL for
* the specific language governing rights and limitations.
*/
#ifndef _NL_LINEAR_SYSTEM_H_
#define _NL_LINEAR_SYSTEM_H_
#include <cassert>
#include <gsl/gsl_linalg.h>
#include <2geom/numeric/matrix.h>
#include <2geom/numeric/vector.h>
namespace Geom { namespace NL {
class LinearSystem
{
public:
LinearSystem(MatrixView & _matrix, VectorView & _vector)
: m_matrix(_matrix), m_vector(_vector), m_solution(_matrix.columns())
{
}
LinearSystem(Matrix & _matrix, Vector & _vector)
: m_matrix(_matrix), m_vector(_vector), m_solution(_matrix.columns())
{
}
const Vector & LU_solve()
{
assert( matrix().rows() == matrix().columns()
&& matrix().rows() == vector().size() );
int s;
gsl_permutation * p = gsl_permutation_alloc(matrix().rows());
gsl_linalg_LU_decomp (matrix().get_gsl_matrix(), p, &s);
gsl_linalg_LU_solve( matrix().get_gsl_matrix(),
p,
vector().get_gsl_vector(),
m_solution.get_gsl_vector()
);
gsl_permutation_free(p);
return solution();
}
const Vector & SV_solve()
{
assert( matrix().rows() >= matrix().columns()
&& matrix().rows() == vector().size() );
gsl_matrix* U = matrix().get_gsl_matrix();
gsl_matrix* V = gsl_matrix_alloc(matrix().columns(), matrix().columns());
gsl_vector* S = gsl_vector_alloc(matrix().columns());
gsl_vector* work = gsl_vector_alloc(matrix().columns());
gsl_linalg_SV_decomp( U, V, S, work );
gsl_vector* b = vector().get_gsl_vector();
gsl_vector* x = m_solution.get_gsl_vector();
gsl_linalg_SV_solve( U, V, S, b, x);
gsl_matrix_free(V);
gsl_vector_free(S);
gsl_vector_free(work);
return solution();
}
MatrixView & matrix()
{
return m_matrix;
}
VectorView & vector()
{
return m_vector;
}
const Vector & solution() const
{
return m_solution;
}
private:
MatrixView m_matrix;
VectorView m_vector;
Vector m_solution;
};
} } // end namespaces
#endif /*_NL_LINEAR_SYSTEM_H_*/
/*
Local Variables:
mode:c++
c-file-style:"stroustrup"
c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
indent-tabs-mode:nil
fill-column:99
End:
*/
// vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:fileencoding=utf-8:textwidth=99 :
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