/usr/include/polymake/fan/tight_span.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 | /* 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_TIGHT_SPAN_H
#define POLYMAKE_TIGHT_SPAN_H
#include "polymake/Matrix.h"
#include "polymake/Vector.h"
#include "polymake/linalg.h"
#include "polymake/Set.h"
#include "polymake/list"
#include "polymake/graph/Decoration.h"
namespace polymake { namespace fan {
//Excludes all faces contained in a list of "boundary faces"
class NoBoundaryCut {
protected:
const std::list<Set<int> >& max_boundary_faces;
const IncidenceMatrix<>& maximal_cones;
public:
NoBoundaryCut(const std::list<Set<int> >& mbf, const IncidenceMatrix<>& mc) :
max_boundary_faces(mbf), maximal_cones(mc) {}
inline bool operator()(const graph::lattice::BasicDecoration& data) const {
if(data.face.size() == 0) return true;
auto face = accumulate(rows(maximal_cones.minor(data.face,All)), operations::mul());
for(auto mf_it : max_boundary_faces)
if(incl(face, mf_it) < 1) return false;
return true;
}
};
template <typename Scalar, typename MTop, typename VTop, typename MatrixTop>
Matrix<Scalar> tight_span_vertices( const GenericMatrix<MTop, Scalar>& points, const GenericIncidenceMatrix<MatrixTop>& VIF, const GenericVector<VTop, Scalar>& lift )
{
const bool full_dim = ( rank(points)==points.cols() );
const int dim = full_dim ? points.cols()+1 : points.cols() ;
Matrix<Scalar> vertices( VIF.rows(), dim );
Matrix<Scalar> eq(points.rows(),dim);
eq.minor(All,sequence(0,points.cols())) = points;
eq.col(0)=lift;
if(full_dim){
eq.col( dim-1 ) = ones_vector<Scalar>(points.rows())-points.minor(All,sequence(1,points.cols()-1))*ones_vector<Scalar>(points.cols()-1);
}
int i = 0;
for(auto it= entire(rows(VIF)); !it.at_end(); ++it, ++i){
vertices.row(i) = null_space(eq.minor(*it,All)).row(0);
if(vertices[i][0]<0)
vertices.row(i)*=-1;
}
return vertices;
}
}}
#endif
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