Hi This email is in reference to the thread: https://archives.skewed.de/hyperkitty/list/graph-tool@skewed.de/thread/VVDN6... As I had said earlier, I cannot share my code with you. I have instead saved and attached the graph with this email. I am not able to run the optimal maximum matching algorithm on this graph. However, I am able to run the heuristic algorithm. I would like to run the optimal algorithm as well. Please let me know if there is some error with this graph format or if there is some error with the library itself. Code to reproduce: from graph_tool.all import Graph, load_graph graph = load_graph("temp.xml.gz") max_cardinality_matching(graph, weight=graph.edge_properties["weight"], bipartite=False, heuristic=False, edges=True) I'm sorry I couldn't reply to the thread itself as I wasn't able to figure out a way to attach a file to the existing thread. Thanks and Regards Chaitanya Agarwal