AssertionError: -6 when trying to generate flux diagrams on Mac

[mjohnson541]

So it seems that the conda binaries we currently pull for graphviz result in an assertion error when generating pngs and similar files preventing generation of flux diagrams images using pydot. This is the same issue as in: ReactionMechanismGenerator/RMG-Py#2180.

While for the moment it isn't feasible to change the binaries because of dependency issues. If you install graphviz with brew and then delete the dot executable in the rms_env (can find this with which dot in the rms_env) RMS will call brew's graphviz instead which will allow it to generate and display the flux diagram.