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/*
GRAPHS - graph theory package for Maxima
Copyright (C) 2007-2011 Andrej Vodopivec <andrej.vodopivec@gmail.com>
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 of the License, or
(at your option) any later version.
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.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
dimacs_export(gr, file, [comments]) := block(
[fl, str],
str: apply(dimacs_export_string, cons(gr, comments)),
fl:openw(file),
printf(fl, str),
close(fl))$
dimacs_export_string(gr, [comments]) := block(
[str:"", names:hash_table(), i:1],
if not(is_graph_or_digraph(gr)) then error("dimacs_export: first argument is not a graph:", gr),
for v in sort(vertices(gr)) do (
set_hash(v, names, i),
i:i+1),
str : sconcat(str, printf(false, "c graph exported from MAXIMA~%")),
for c in comments do (
str: sconcat(str, printf(false, "c ~a~%", c))),
if is_graph(gr) then
str: sconcat(str, printf(false, "p edge ~a ~a~%", graph_order(gr), graph_size(gr)))
else
str: sconcat(str, printf(false, "p arc ~a ~a~%", graph_order(gr), graph_size(gr))),
for v in vertices(gr) do (
if get_vertex_label(v, gr)#false then
str: sconcat(str, printf(false, "n ~a ~a~%", get_hash(v, names), get_vertex_label(v, gr)))),
for e in edges(gr) do block(
[u:get_hash(first(e), names), v:get_hash(second(e), names), u1, v1],
if is_graph(gr) then
[u1,v1] : [min(u,v), max(u,v)]
else
[u1,v1] : [u, v],
if get_edge_weight(e, gr)=1 then
str: sconcat(str, printf(false, "e ~a ~a~%", u1, v1))
else
str: sconcat(str, printf(false, "e ~a ~a ~a~%", u1, v1, get_edge_weight(e, gr)))),
str)$
dimacs_import(file, [mv]) := block(
[n, fl, line, elist:[], t, e, v_labels:[], g, dir:false],
if length(mv)=1 and integerp(mv[1]) then mv:mv[1]
else mv:1,
fl:openr(file),
l:readline(fl),
while l#false do (
t:tokens(l),
if length(t) > 0 then (
if t[1]="p" then (
n:read_string(third(t)),
dir:second(t),
if dir="edges" or dir="edge" then dir:false
else dir:true)
else if t[1]="n" and length(t)>=3 then
v_labels:cons([read_string(second(t))-mv, third(t)], v_labels)
else if t[1]="e" then (
e : map(lambda([u], read_string(u)-mv), [second(t), third(t)]),
if length(t)=3 then
elist:cons(e, elist)
else
elist:cons([e, read_string(fourth(t))], elist))
else if t[1]#"c" then error("import_dimacs: wrong file format")),
l:readline(fl)),
close(fl),
if not(integerp(n)) then error("import_dimacs: wrong file format"),
g : create_graph(n,elist,'directed=dir),
for v in v_labels do set_vertex_label(v[1], v[2], g),
g)$
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