def calculate_degree(graph: PropertyGraph,
in_degree_property,
out_degree_property,
weight_property=None):
"""
Calculate the (potentially weighted) in and out degrees of a graph.
The function will modify the given graph by adding two new node properties,
one for the in degree and one for the out degree. Nothing is returned.
Parameters:
graph: a PropertyGraph
in_degree_property: the property name for the in degree
out_degree_property: the property name for the out degree
weight_property: an edge property to use in calculating the weighted degree
"""
num_nodes = graph.num_nodes()
nout = LargeArray[np.uint64](num_nodes, AllocationPolicy.INTERLEAVED)
nin = LargeArray[np.uint64](num_nodes, AllocationPolicy.INTERLEAVED)
do_all(range(num_nodes), initialize_in_degree(nin.as_numpy()), steal=False)
# are we calculating weighted degree?
if not weight_property:
count_operator = count_in_and_out_degree(graph, nout.as_numpy(),
nin.as_numpy())
else:
count_operator = count_weighted_in_and_out_degree(
graph, nout.as_numpy(), nin.as_numpy(),
graph.get_edge_property(weight_property))
do_all(range(num_nodes), count_operator, steal=True)
graph.add_node_property(
pyarrow.table({
in_degree_property: nin,
out_degree_property: nout
}))
def create_distance_array(g: PropertyGraph, source, length_property):
a = np.empty(len(g),
dtype=dtype_of_pyarrow_array(
g.get_edge_property(length_property)))
# TODO(amp): Remove / 4
infinity = dtype_info(a.dtype).max / 4
a[:] = infinity
a[source] = 0
return a
def sssp(graph: PropertyGraph, source, length_property, shift, property_name):
dists = create_distance_array(graph, source, length_property)
# Define the struct type here so it can depend on the type of the weight property
UpdateRequest = np.dtype([("src", np.uint32), ("dist", dists.dtype)])
init_bag = InsertBag[UpdateRequest]()
init_bag.push((source, 0))
t = StatTimer("Total SSSP")
t.start()
for_each(
init_bag,
sssp_operator(graph, dists, graph.get_edge_property(length_property)),
worklist=OrderedByIntegerMetric(obim_indexer(shift)),
disable_conflict_detection=True,
loop_name="SSSP",
)
t.stop()
print("Elapsed time: ", t.get(), "milliseconds.")
graph.add_node_property(pyarrow.table({property_name: dists}))
