/usr/include/polymake/group/representations.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 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 | /* 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 __GROUP_REPRESENTATIONS_H
#define __GROUP_REPRESENTATIONS_H
#include "polymake/Array.h"
#include "polymake/hash_map"
#include "polymake/SparseMatrix.h"
#include "polymake/Rational.h"
namespace polymake { namespace group {
namespace {
template<typename SetType>
class InducedAction {
protected:
int degree;
const Array<SetType>& domain;
const hash_map<SetType, int>& index_of;
Array<int> inverse_permutation(const Array<int>& perm) const {
Array<int> inv_perm(perm.size());
for (int i=0; i<perm.size(); ++i)
inv_perm[perm[i]] = i;
return inv_perm;
}
public:
InducedAction(int degree,
const Array<SetType>& domain,
const hash_map<SetType, int>& index_of)
: degree(degree)
, domain(domain)
, index_of(index_of)
{}
int index_of_image(const Array<int>& perm,
const SetType& elt) const {
SetType image;
image.resize(perm.size());
for (typename Entire<SetType>::const_iterator sit = entire(elt); !sit.at_end(); ++sit)
image += perm[*sit];
return index_of.at(image);
}
int index_of_inverse_image(const Array<int>& perm,
const SetType& elt) const {
Array<int> inv_perm(inverse_permutation(perm));
SetType inv_image;
inv_image.resize(inv_perm.size());
for (typename Entire<SetType>::const_iterator sit = entire(elt); !sit.at_end(); ++sit)
inv_image += inv_perm[*sit];
return index_of.at(inv_image);
}
int index_of_inverse_image(const Array<int>& perm,
const int elt_index) const {
return index_of_inverse_image(perm, domain[elt_index]);
}
SparseMatrix<Rational> induced_rep(const Array<int>& perm) const {
SparseMatrix<Rational> induced_rep(degree, degree);
int col_index(0);
for (typename Entire<Array<SetType> >::const_iterator dit = entire(domain); !dit.at_end(); ++dit, ++col_index) {
induced_rep(index_of_image(perm, *dit), col_index) = 1;
}
return induced_rep;
}
};
} // end anonymous namespace
} }
#endif // __GROUP_REPRESENTATIONS_H
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