def part_graph(nparts, adjacency=None, xadj=None, adjncy=None, vweights=None, eweights=None, recursive=None):
"""Return a partition (cutcount, part_vert) into nparts for an input graph.
The input graph is given as either a Pythonic way as the `adjacency' parameter
or in the direct C-like way that Metis likes as `xadj' and `adjncy'. It
is an error to specify both graph inputs.
The Pythonic graph specifier `adjacency' is required to have the following
properties:
- len(adjacency) needs to return the number of vertices
- adjacency[i] needs to return an iterable of vertices adjacent to vertex i.
Both directions of an undirected graph edge are required to be stored.
For details on how `xadj' and `adjncy' are specified, see the Metis
documentation.
"""
xadj, adjncy = _prepare_graph(adjacency, xadj, adjncy)
if recursive is None:
if nparts > 8:
recursive = False
else:
recursive = True
from pymetis._internal import part_graph
if nparts == 1:
# metis has a bug in this case--it disregards the index base
return 0, [0] * (len(xadj) - 1)
return part_graph(nparts, xadj, adjncy, vweights, eweights, recursive)
def part_graph(nparts,
adjacency=None,
xadj=None,
adjncy=None,
vweights=None,
eweights=None,
recursive=None):
"""Return a partition (cutcount, part_vert) into nparts for an input graph.
The input graph is given in either a Pythonic way as the `adjacency' parameter
or in the direct C-like way that Metis likes as `xadj' and `adjncy'. It
is an error to specify both graph inputs.
The Pythonic graph specifier `adjacency' is required to have the following
properties:
- len(adjacency) needs to return the number of vertices
- adjacency[i] needs to be an iterable of vertices adjacent to vertex i.
Both directions of an undirected graph edge are required to be stored.
If you would like to use *eweights* (edge weights), you need to use the
xadj/adjncy way of specifying graph connectivity. This works as follows:
The adjacency structure of the graph is stored as follows: The
adjacency list of vertex *i* is stored in array *adjncy* starting at
index ``xadj[i]`` and ending at (but not including) index ``xadj[i +
1]``. That is, for each vertex i, its adjacency list is stored in
consecutive locations in the array *adjncy*, and the array *xadj* is
used to point to where it begins and where it ends.
The weights of the edges (if any) are stored in an additional array
called *eweights*. This array contains *2m* elements (where *m* is the
number of edges, taking into account the undirected nature of the
graph), and the weight of edge ``adjncy[j]`` is stored at location
``adjwgt[j]``. The edge-weights must be integers greater than zero. If
all the edges of the graph have the same weight (i.e., the graph is
unweighted), then the adjwgt can be set to ``None``.
(quoted with slight adaptations from the Metis docs)
"""
xadj, adjncy = _prepare_graph(adjacency, xadj, adjncy)
if recursive is None:
if nparts > 8:
recursive = False
else:
recursive = True
from pymetis._internal import part_graph
if nparts == 1:
# metis has a bug in this case--it disregards the index base
return 0, [0] * (len(xadj) - 1)
return part_graph(nparts, xadj, adjncy, vweights, eweights, recursive)
def part_graph(nparts, adjacency=None, xadj=None, adjncy=None,
vweights=None, eweights=None, recursive=None):
"""Return a partition (cutcount, part_vert) into nparts for an input graph.
The input graph is given in either a Pythonic way as the `adjacency' parameter
or in the direct C-like way that Metis likes as `xadj' and `adjncy'. It
is an error to specify both graph inputs.
The Pythonic graph specifier `adjacency' is required to have the following
properties:
- len(adjacency) needs to return the number of vertices
- adjacency[i] needs to be an iterable of vertices adjacent to vertex i.
Both directions of an undirected graph edge are required to be stored.
If you would like to use *eweights* (edge weights), you need to use the
xadj/adjncy way of specifying graph connectivity. This works as follows:
The adjacency structure of the graph is stored as follows: The
adjacency list of vertex *i* is stored in array *adjncy* starting at
index ``xadj[i]`` and ending at (but not including) index ``xadj[i +
1]``. That is, for each vertex i, its adjacency list is stored in
consecutive locations in the array *adjncy*, and the array *xadj* is
used to point to where it begins and where it ends.
The weights of the edges (if any) are stored in an additional array
called *eweights*. This array contains *2m* elements (where *m* is the
number of edges, taking into account the undirected nature of the
graph), and the weight of edge ``adjncy[j]`` is stored at location
``adjwgt[j]``. The edge-weights must be integers greater than zero. If
all the edges of the graph have the same weight (i.e., the graph is
unweighted), then the adjwgt can be set to ``None``.
(quoted with slight adaptations from the Metis docs)
"""
xadj, adjncy = _prepare_graph(adjacency, xadj, adjncy)
if recursive is None:
if nparts > 8:
recursive = False
else:
recursive = True
from pymetis._internal import part_graph
if nparts == 1:
# metis has a bug in this case--it disregards the index base
return 0, [0] * (len(xadj)-1)
return part_graph(nparts, xadj, adjncy, vweights, eweights, recursive)
