ShyLU/FROSch: Running tests with 1 mpi rank results in runtime error
Created by: chochmuth
After fix #4505 it should be possible to run the Thyra_Xpetra_Laplace tests in serial.
However, when running a serial test which solves the harmonic extension with Klu2 I get the following runtime error from Amesos2:
Amesos2 Runtime Error: sp_colind returned null.
For the speacial case of 1 mpi rank we need to check wether to compute extension or not.