def degree_assortativity_coefficient(
graph: PropertyGraph,
source_degree_type: DegreeType = DegreeType.OUT,
destination_degree_type: DegreeType = DegreeType.IN,
weight=None,
):
"""
Calculates and returns the degree assortativity of a given graph.
Paramaters:
* graph: the PropertyGraph to be analyzed
* source_degree_type: description of degree type to consider for the source node on an edge
expected values are DegreeType.IN or DegreeType.OUT
* destination_degree_type: description the degree type to consider for the destination node on an edge
expected values are DegreeType.IN or DegreeType.OUT
* weight (optional): edge property to use if using weighted degrees
"""
# get the tables associated with the degree types of the source and destination nodes
calculate_degree(graph, "temp_DegreeType.IN", "temp_DegreeType.OUT",
weight)
source_degree = graph.get_node_property("temp_" + str(source_degree_type))
destination_degree = graph.get_node_property("temp_" +
str(destination_degree_type))
try:
# Calculate the average in and out degrees of graph
# (with respect to number of edges, not number of nodes)
num_edges = graph.num_edges()
source_average, destination_average = average_degree(
graph, num_edges, source_degree, destination_degree)
# Calculate the numerator (product of deviation from mean)
# and the factors of the denominator (square deviation from mean)
product_of_dev = GAccumulator[float](0)
square_of_source_dev = GAccumulator[float](0)
square_of_destination_dev = GAccumulator[float](0)
do_all(
range(graph.num_nodes()),
degree_assortativity_coefficient_operator(
graph,
source_degree,
source_average,
destination_degree,
destination_average,
product_of_dev,
square_of_source_dev,
square_of_destination_dev,
),
steal=True,
loop_name="degree assortativity coefficient calculation",
)
return product_of_dev.reduce() / sqrt(
square_of_source_dev.reduce() * square_of_destination_dev.reduce())
finally:
graph.remove_node_property("temp_DegreeType.IN")
graph.remove_node_property("temp_DegreeType.OUT")
def test_commit(property_graph):
# TODO(amp): mark_all_properties_persistent shouldn't be required. Why is it?
property_graph.mark_all_properties_persistent()
with TemporaryDirectory() as tmpdir:
property_graph.path = tmpdir
property_graph.write()
del property_graph
property_graph = PropertyGraph(tmpdir)
assert property_graph.num_nodes() == 29092
assert property_graph.num_edges() == 39283
assert len(property_graph.node_schema()) == 31
assert len(property_graph.edge_schema()) == 19
