OK, when I write "sudo apt-get install python3-graph-tool", it says "python3-graph-tool is already the newest version (2.31-2).". Then, when I want to run the code shown below: #Start of the code: *# Girvan - Newman # igraph import networkx as nx from igraph import * import tempfile import igraph as ig import pyintergraph from graph_tool.all import * #g = read_graph("Network.graphml", format = c("graphml")) g = nx.read_graphml("Network.graphml") # nx_graph = nx.karate_club_graph() graph_tool_graph = pyintergraph.nx2gt(g, labelname="node_label") igraph_graph = pyintergraph.gt2igraph(graph_tool_graph, labelname="node_label") # reversed_nx_graph = pyintergraph.igraph2nx(igraph_graph) # fobj = tempfile.NamedTemporaryFile() g2 = nx.path_graph(4) nx.write_gml(g2, 'test.gml') # g = Graph.Read_GML("test.gml") d = igraph_graph.community_edge_betweenness() p = d.as_clustering() Q = igraph_graph.modularity(p) print(d) print(p) print(Q) # End of the code I write " python3 GirvanIgraph.py" in a terminal and GirvanIgraph.py is the name of the file, it shows the following error: Traceback (most recent call last): File "GirvanIgraph.py", line 9, in <module> from graph_tool.all import * ModuleNotFoundError: No module named 'graph_tool' -- Sent from: http://main-discussion-list-for-the-graph-tool-project.982480.n3.nabble.com/