extracting face connectivity from a 3D mesh

[jthunes]

I have an application where I need the element-to-face and face-to-element connectivity in addition to the element-to-node connectivity of a 3D (tri3 or hex8) mesh stored in exodus format. This face connectivity is reasonably simple to construct from the nodal connectivity, but my (admittedly naive) implementation is taking a significant amount of the total runtime of my program.

Before I refactor my implementation into a more performant form, I wanted to confirm that there wasn't an existing option to extract from the meshio object (using meshio.read). My read of the code, tests, and previous discussions did not show any likely candidates.

Any suggestions would be appreciated.