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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 PURPSE. See the
# GNU General Public License for more details.
#-------------------------------------------------------------------------------
REQUIRE graph::compare.rules
object Matroid {
rule AUTOMORPHISM_GROUP.PERMUTATION_ACTION(new).DEGREE, AUTOMORPHISM_GROUP.PERMUTATION_ACTION(new).GENERATORS : BASES, N_ELEMENTS {
# Make sure the IncidenceMatrix has the right number of cols
my $total_matrix = new IncidenceMatrix(@{$this->BASES}, $this->N_ELEMENTS);
my @gens = map { $_->second } @{automorphisms($total_matrix)};
if (@gens == 0) {
# The identity is not returned by automorphisms
push @gens, [0 .. $this->N_ELEMENTS-1];
}
$this->AUTOMORPHISM_GROUP->PERMUTATION_ACTION->DEGREE = $this->N_ELEMENTS;
$this->AUTOMORPHISM_GROUP->PERMUTATION_ACTION->GENERATORS = \@gens;
$this->AUTOMORPHISM_GROUP->PERMUTATION_ACTION->description = "permutation action of automorphism group";
$this->AUTOMORPHISM_GROUP->description = "Automorphism group of ".$this->name if $this->name;
$this->AUTOMORPHISM_GROUP->name = "Aut";
}
weight 5.10;
}
# Local Variables:
# mode: perl
# cperl-indent-level: 3
# indent-tabs-mode:nil
# End:
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