Hello, I get a segmentation fault when trying to plot a loop with graphviz_draw(). Here is a minimal example to reproduce the error: import graph_tool.all as gt g = gt.Graph() v0 = g.add_vertex() v1 = g.add_vertex() e01 = g.add_edge(v0,v1) e11 = g.add_edge(v1,v1) # loop gt.graphviz_draw(g) I have version 2.33 of python3-graph-tool installed on my computer which runs on Linux Mint 19.2 Tina (based on Ubuntu 18.04 LTS, bionic). My graphviz version is 2.40.1-2. It works fine if I don't add the loop e11 to the graph. It works fine if I use gt.graph_draw() instead of gt.graphviz_draw() It works fine if I use graphviz directly (via a .dot file). It did work fine in earlier versions of graph_tool. Can anyone reproduce this? Best regards Rolf -- ----------------------------------------------------------------------- Rolf Sander phone: [+49] 6131/305-4610 Max-Planck Institute of Chemistry email: rolf.sander@mpic.de PO Box 3060, 55020 Mainz, Germany homepage: www.rolf-sander.net ----------------------------------------------------------------------- https://www.encyclopedia-of-geosciences.net https://www.geoscientific-model-development.net -----------------------------------------------------------------------