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MetisIntro » Graphgen.py

Thomas Jahns, 12/03/2010 04:14 PM

 
#!/usr/bin/python
# -*- coding: utf-8 -*-
"""
Graphgen generates a rectangular graph in the METIS graph format

Usage:
Graphgen.py n -- generate a square n x n graph
Graphgen.py n m -- generate a n x m graph

'n' and 'm' must be integers
"""

__author__ = """Florian Wilhelm (Florian.Wilhelm@kit.edu)"""
__date__ = """26.03.2009"""

import sys

if len(sys.argv) <= 1:
print __doc__
sys.exit(1)
elif len(sys.argv) == 2:
u = int(sys.argv[1])
v = u
elif len(sys.argv) >= 3:
u, v = int(sys.argv[1]), int(sys.argv[2])

filename = "graph-%sx%s"%(u,v)
vertices = u * v
edges = u * (v - 1) + v * (u - 1)

fh = open(filename, 'w')
fh.writelines("%s %s\n"%(vertices, edges))

for line in range(1, vertices + 1):
neighbors = [line - 1, line - v, line + v, line + 1]
if line % v == 1 or v == 1: # left border
neighbors.remove(line - 1)
if line % v == 0: # right border
neighbors.remove(line + 1)
if line <= v: # lower border
neighbors.remove(line - v)
if line > u*v - v: # upper border
neighbors.remove(line + v)
neighbors = map(str, neighbors)
fh.writelines(" ".join(neighbors) + "\n")

fh.close()

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