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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.
#-------------------------------------------------------------------------------
CREDIT plantri
plantri is a program for generation of certain types of planar graphs.
The authors are Gunnar Brinkmann (University of Ghent) and Brendan McKay (Australian National University).
https://users.cecs.anu.edu.au/~bdm/plantri/
# path to the plantri executable
custom $plantri;
CONFIGURE {
find_program($plantri, "plantri") or return;
}
# @category Data Conversion
# Convert the output of [[wiki:external_software#plantri]] program into polymake Polytope object.
# Returns an Array of combinatorial types of simplicial 3-polytopes (or their duals).
# @param Int number of vertices
# @param String options (not affecting the output format) as described in the plantri manual
# @return Array<Polytope>
# @example Combinatorial types of simplicial 3-polytopes with 6 vertices.
# > $A = plantri_list(6);
# > print $A->size();
# | 2
# Distribution of vertex degrees of the first polytope in that list.
# > print histogram($A->[0]->VERTEX_DEGREES);
# | {(3 2) (4 2) (5 2)}
# @example Simple 3-polytopes with seven facets.
# > $B = plantri_list(7,"-d");
# > print $B->size();
# | 5
# > print $B->[0]->F_VECTOR;
# | 10 15 7
user_function plantri_list {
my $n_args = scalar @_;
if ($n_args < 1 || $n_args > 2){ die "plantri: <number of vertices> [<plantri options>]" }
my ($num_verts, $options) = @_;
my $plantri_doublecode_call = $plantri . " $options -T " . $num_verts;
my $plantri_output = `$plantri_doublecode_call`;
my @triangulations = split /\n/, $plantri_output;
my $n_tris = scalar @triangulations;
my $return_array = new Array<Polytope>($n_tris);
for(my $tri_index = 0; $tri_index < $n_tris; $tri_index++) {
# Get the data associated to the chosen triangulation
my @chosen_tri = split /(\d+)/, $triangulations[$tri_index];
# Get number of vertices, and vertex information
my $n_verts = $chosen_tri[1];
my @v= split / /, $chosen_tri[2];
shift(@v);
my $vertices = new Array<String>(@v);
# Get number of faces and face information
my $n_facets = $chosen_tri[3];
my @f= split / /, $chosen_tri[4];
shift(@f);
my $facets = new Array<String>(@f);
# Initiate the VIF matrix
my $VIF_out = new IncidenceMatrix($n_facets,$n_verts);
# For each vertex, check which faces contains it
for (my $vert_id = 0; $vert_id < $n_verts; $vert_id++) {
# For each edge list given for each vertex, we add the first edge to the last to get all edge pairs that contains the chosen vertex
my $myvert = $vertices->[$vert_id] . substr($vertices->[$vert_id], 0, 1);
for (my $i = 0; $i < length($myvert)-1; $i++) {
# Get each consecutive edges in the edge list, and check if it appears on cyclic edge list given by the faces
my $lookfor = scalar reverse substr($myvert,$i,2);
for (my $facet_id = 0; $facet_id < $n_facets; $facet_id++) {
my $myfacet = $facets->[$facet_id] . substr($facets->[$facet_id], 0, 1);
if (index($myfacet,$lookfor) != -1){
#If edges from vertex pair is in the face, then add this incidence relation.
$VIF_out->elem($facet_id,$vert_id) = 1;
}
}
}
}
$return_array->[$tri_index] = new Polytope(COMBINATORIAL_DIM=>3, VERTICES_IN_FACETS=>$VIF_out);
}
return($return_array);
}
# Local Variables:
# mode: perl
# cperl-indent-level: 3
# indent-tabs-mode:nil
# End:
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