automatically symmetrizing in GAMG (only when needed)?
Error message a user gets:
Mat has an un-symmetric graph. Use '-mpi_pc_gamg_sym_graph true' to symmetrize the graph or '-mpi_pc_gamg_threshold -1' if the matrix is structurally symmetric.
Should it instead only end the program with this error message if MAT_STRUCTURALLY_SYMMETRIC has been set by the user and otherwise when it detects the lack of symmetry here in the code just automatically back up the algorithm and symmetrize the graph for the user?
I would argue yes. Based on the philosophy "if the computer can do it for you instead of telling you to do it then the computer should just do it for you".
With a PetscInfo informing you of this, and if this backup occurring could also go into the PCView_GAMG() output. If we had a PCMonitor_GAMG the monitor could also note it there but currently, we do not have PC monitors.