/usr/include/polymake/graph/incidence_matrix.h is in libpolymake-dev-common 3.2r2-3.
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 | /* Copyright (c) 1997-2018
Ewgenij Gawrilow, Michael Joswig (Technische Universitaet Berlin, Germany)
http://www.polymake.org
This program is free software; you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by the
Free Software Foundation; either version 2, or (at your option) any
later version: http://www.gnu.org/licenses/gpl.txt.
This program 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 General Public License for more details.
--------------------------------------------------------------------------------
*/
#ifndef POLYMAKE_GRAPH_INCIDENCE_MATRIX_H
#define POLYMAKE_GRAPH_INCIDENCE_MATRIX_H
#include "polymake/client.h"
#include "polymake/SparseMatrix.h"
#include "polymake/Graph.h"
namespace polymake { namespace graph {
namespace {
template <typename TGraph>
SparseMatrix<int> incidence_matrix_impl(const GenericGraph<TGraph>& G, int s=1)
{
SparseMatrix<int> E (G.top().nodes(), G.top().edges());
int col(0);
for (auto eit = entire(edges(G.top())); !eit.at_end(); ++eit, ++col) {
E(eit.from_node(), col) = s;
E(eit.to_node(), col) = 1;
}
return E;
}
} // end anonymous namespace
template <typename TGraph>
SparseMatrix<int> incidence_matrix(const GenericGraph<TGraph>& p)
{
return incidence_matrix_impl(p.top(), 1);
}
template<typename TGraph>
SparseMatrix<int> signed_incidence_matrix(const GenericGraph<TGraph>& p)
{
return incidence_matrix_impl(p.top(), -1);
}
template<typename Dir>
SparseMatrix<int> incidence_matrix(perl::Object p)
{
Graph<Dir> G=p.give("ADJACENCY");
return incidence_matrix_impl(G, 1);
}
template<typename Dir>
SparseMatrix<int> signed_incidence_matrix(perl::Object p)
{
Graph<Dir> G=p.give("ADJACENCY");
return incidence_matrix_impl(G, -1);
}
} }
#endif
// Local Variables:
// mode:C++
// c-basic-offset:3
// indent-tabs-mode:nil
// End:
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