Example of using SNAP with the multiprocessing module and a progress bar (tqdm)

snap-multiprocessing.py

import sys
import multiprocessing
import tqdm
import snap

# the graph needs to be global so workers can access it after forking
GRAPH = None

# task: compute eccentricy of a node
def compute_ecc(node_id):
    global GRAPH
    return snap.GetNodeEcc(GRAPH, node_id)

# main function
def main():
    global GRAPH
    GRAPH = snap.TUNGraph.Load(snap.TFIn(sys.argv[1]))
    print "loaded %d nodes and %d edges" % (GRAPH.GetNodes(), GRAPH.GetEdges())

    # parallel compute eccentricity of all nodes
    pool = None
    try:
        pool = multiprocessing.Pool()
        num_nodes = GRAPH.GetNodes()
        node_ids = (n.GetId() for n in GRAPH.Nodes())
        iterator = pool.imap_unordered(compute_ecc, node_ids)
        accumulator = 0.0
        for ecc in tqdm.tqdm(iterator, total=num_nodes, desc="ecc", unit="node"):
            accumulator += ecc
        print "mean node eccentricity = %f" % (accumulator / num_nodes)
    finally:
        if pool:
            pool.close()
            pool.join()

if __name__ == "__main__":
    main()