def eval_map_equation(g, partitionobj):
"""Return the map equation score for a given partition."""
g1 = nx.convert_node_labels_to_integers(g, label_attribute="name")
scoremapeq = 0
partition = partitionobj.communities
part = dict()
for i in range(len(partition)):
for ind in partition[i]:
part[ind] = i
im = Infomap("--silent --no-infomap") # Don't change the partition.
for e in g1.edges():
im.addLink(e[0], e[1])
im.initial_partition = part
im.run()
scoremapeq = im.codelength
return scoremapeq
}
# Only two modules, splitting the chain in the middle
partition2 = {
0: 0,
1: 0,
2: 0,
3: 0,
4: 2,
5: 2,
6: 2,
7: 2,
}
# Set initial partition on the Infomap instance to keep it during multiple runs
im.initial_partition = partition1
im.run(no_infomap=True)
print(
f"Partition one with {im.num_top_modules} modules -> codelength: {im.codelength:.8f} bits"
)
# Set initial partition as run parameter to only use it for this run (will be restored to partition1 after)
im.run(initial_partition=partition2, no_infomap=True)
print(
f"Partition two with {im.num_top_modules} modules -> codelength: {im.codelength:.8f} bits"
)