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
|
/* Copyright (c) 1997-2024
Ewgenij Gawrilow, Michael Joswig, and the polymake team
Technische Universität Berlin, Germany
https://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.
--------------------------------------------------------------------------------
*/
#pragma once
#include "polymake/Set.h"
#include "polymake/IncidenceMatrix.h"
#include "polymake/FacetList.h"
namespace polymake { namespace polytope {
/// @retval row indices of (non-facets, hidden equations), first includes second
template <typename IM>
std::pair<Set<Int>, Set<Int>>
compress_incidence(const GenericIncidenceMatrix<IM>& VIF)
{
Set<Int> non_facets, hidden_equations;
const Int nv = VIF.cols();
FacetList facets(nv);
for (auto f=entire(rows(VIF)); !f.at_end(); ++f) {
if (f->size() == nv) {
facets.skip_facet_id();
non_facets.push_back(f.index());
hidden_equations.push_back(f.index());
} else if (! facets.replaceMax(*f, inserter(non_facets))) {
non_facets.push_back(f.index());
}
}
return std::make_pair(non_facets, hidden_equations);
}
} }
// Local Variables:
// mode:C++
// c-basic-offset:3
// indent-tabs-mode:nil
// End:
|
