def main(args):
parser = argparse.ArgumentParser()
parser.add_argument('output',
metavar='graph.pickle',
help='Ouput graph file')
parser.add_argument(
'--connection',
default='postgresql://*****:*****@localhost/osrm',
help='Postgres connection string. Default %(default)s')
parser.add_argument('--prune',
action='store_true',
help='Collapse redundant edges, prune tails')
parser.add_argument('--verbose',
action='store_true',
help='Increase logging level')
args = parser.parse_args()
logging.basicConfig(
level=logging.INFO if args.verbose else logging.WARNING)
log.info("Creating DB engine")
engine = create_engine(args.connection, echo=False)
log.info("Creating DB session")
Session = sessionmaker(bind=engine)
session = Session()
g = build_graph(session)
if args.prune:
log.info("Collapsing unidirectional strings")
pruned = graphtools.collapse_degree_2_vtxs(g)
log.info("Removed %i thru-nodes", pruned)
log.info("Collapsing bidirectional strings")
pruned = graphtools.collapse_bidirectional_streets(g)
log.info("Removed %i thru-nodes", pruned)
log.info("Snipping tails")
snipped = graphtools.delete_degree_1_vtxs(g)
log.info("Removed %i tails", snipped)
loners = graphtools.delete_degree_0_vtxs(g)
log.info("Removed %i loner-nodes (should be zero)", loners)
redundancies = graphtools.identify_rendudant_nodes(g)
log.info("Marked %i nodes as redundant", redundancies)
log.info("Saving graph to %s", args.output)
g.save(args.output)
def main(args):
parser = argparse.ArgumentParser()
parser.add_argument('output', metavar='graph.pickle',
help='Ouput graph file')
parser.add_argument(
'--connection',
default='postgresql://*****:*****@localhost/osrm',
help='Postgres connection string. Default %(default)s'
)
parser.add_argument('--prune', action='store_true',
help='Collapse redundant edges, prune tails')
parser.add_argument('--verbose', action='store_true',
help='Increase logging level')
args = parser.parse_args()
logging.basicConfig(
level=logging.INFO if args.verbose else logging.WARNING)
log.info("Creating DB engine")
engine = create_engine(args.connection, echo=False)
log.info("Creating DB session")
Session = sessionmaker(bind=engine)
session = Session()
g = build_graph(session)
if args.prune:
log.info("Collapsing unidirectional strings")
pruned = graphtools.collapse_degree_2_vtxs(g)
log.info("Removed %i thru-nodes", pruned)
log.info("Collapsing bidirectional strings")
pruned = graphtools.collapse_bidirectional_streets(g)
log.info("Removed %i thru-nodes", pruned)
log.info("Snipping tails")
snipped = graphtools.delete_degree_1_vtxs(g)
log.info("Removed %i tails", snipped)
loners = graphtools.delete_degree_0_vtxs(g)
log.info("Removed %i loner-nodes (should be zero)", loners)
redundancies = graphtools.identify_rendudant_nodes(g)
log.info("Marked %i nodes as redundant", redundancies)
log.info("Saving graph to %s", args.output)
g.save(args.output)
def test_collapse_bidirectional_streets():
g = igraph.Graph(directed=True)
# Make a 1x3 rectangle, where the length-3 edges are bidirectional
g.add_vertices(8)
# unidirectional ends
g.add_edges([
(0, 1),
(4, 5)
])
# bidirectional side #1. Let's make it
# so only 2/3 of this side is bi-directional
g.add_edges([
# zero has degree 3
(0, 7),
(7, 0),
(6, 7),
(7, 6),
(6, 5),
# missing (5, 6), so we should
# only collapse node 7.
])
# fully bidirectional side #2.
g.add_edges([
# one has degree 3
(1, 2),
(2, 1),
(2, 3),
(3, 2),
(3, 4),
(4, 3),
])
# sides have flow=2
# top has flow=3
# bottom has flow=4
g.es["weight"] = [2]*2 + [3]*5 + [4]*6
eq_(len(g.vs), 8)
eq_(len(g.es), 13)
ret = gt.collapse_bidirectional_streets(g)
eq_(ret, 3)
eq_(len(g.vs), 5)
eq_(len(g.es), 7)
