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/* 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/hash_set"
#include "polymake/Set.h"
#include "polymake/Array.h"
#include "polymake/group/permlib.h"
namespace polymake { namespace polytope {
Array<Array<Int>> induced_symmetry_group_generators(Int n_,
const Array<Array<Int>>& sym_group_generators,
const Array<Set<Set<Set<Int>>>>& face_orbits)
{
const permlib::dom_int n = permlib::safe_to_dom_int(n_);
typedef permlib::Permutation PERM;
typedef permlib::SchreierTreeTransversal<PERM> TRANSVERSAL;
typedef permlib::BSGS<PERM, TRANSVERSAL> BSGSType;
// construct BSGS of symmetry group
permlib::SchreierSimsConstruction<PERM, TRANSVERSAL> schreierSims(n);
std::list<PERM::ptr> gen_list;
for (auto perm = entire(sym_group_generators); !perm.at_end(); ++perm){
PERM::ptr gen(new PERM((*perm).begin(), (*perm).end()));
gen_list.push_back(gen);
}
BSGSType sym_bsgs = schreierSims.construct(gen_list.begin(), gen_list.end());
// prepare search without DCM pruning
typedef Set<Set<Int>> Container;
typedef Array<Set<Container>> ArrayType;
typedef permlib::LayeredSetSystemStabilizerPredicate<PERM, Container, ArrayType> PredType;
permlib::classic::SetSystemStabilizerSearch<BSGSType, TRANSVERSAL, PredType> backtrackSearch(sym_bsgs, 0);
backtrackSearch.construct(n, face_orbits);
// start the search
BSGSType stabilizer(n);
backtrackSearch.search(stabilizer);
// extract a strong generating set
Array<Array<Int>> new_bsgs(stabilizer.S.size());
auto pit = entire(new_bsgs);
for (const auto& perm : stabilizer.S)
*pit++ = group::PermlibGroup::perm2Array(perm);
return new_bsgs;
}
} } // end namespaces
// Local Variables:
// mode:C++
// c-basic-offset:3
// indent-tabs-mode:nil
// End:
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