/usr/include/polymake/graph/bipartite.tcc is in polymake 3.0r2-2+b1.
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 | /* Copyright (c) 1997-2015
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.
--------------------------------------------------------------------------------
*/
#include "polymake/graph/BFSiterator.h"
#include "polymake/graph/bipartite.h"
#include "polymake/graph/connected.h"
#include <cstdlib>
namespace polymake { namespace graph {
class BipartiteColoring {
protected:
std::vector<int> color;
int sign;
public:
BipartiteColoring();
template <typename Graph>
BipartiteColoring(const GenericGraph<Graph>& G, int start_node)
: color(G.top().dim(),0), sign(1)
{
if (!color.empty()) color[start_node]=1; else sign=0;
}
template <typename Graph>
void reset(const GenericGraph<Graph>&, int start_node)
{
fill(entire(color),0);
if (!color.empty()) color[start_node]=1, sign=1; else sign=0;
}
bool seen(int n) const { return color[n]!=0; }
void add(int n, int n_from)
{
sign += color[n]=-color[n_from];
}
static const bool check_edges=true;
void check(int n, int n_from)
{
if (color[n]==color[n_from]) throw n;
}
int get_sign() const { return std::abs(sign); }
int get_color(int n) const { return color[n]; }
};
template <typename Graph>
int bipartite_sign(const GenericGraph<Graph,Undirected>& G)
{
connected_components_iterator<Graph> C(G);
int signature=0;
while (!C.at_end()) {
int this_node=C->front();
BFSiterator<Graph, Visitor<BipartiteColoring> > it(G, this_node);
try {
while (!it.at_end()) ++it;
} catch (int) {
return -1;
}
signature += it.node_visitor().get_sign();
++C;
}
return signature;
}
} }
// Local Variables:
// mode:C++
// c-basic-offset:3
// indent-tabs-mode:nil
// End:
|