Two FE codes ready for cobra use and scaling tests: "inverse_mass_test" and "maxwell_psydac"
- Added classes for handling linear operators: compose, sum, multiply with sclar, invert. Added subclass LinOpWithTranspose.
- Added preconditioners for the mass matrix, based on fft.
- Shortened the unit tests in ci.
- Adapted push_maxwell to new linear operators.
- Added pcg solver parameters in .yml file, minor bug fix in DATA module file close. maxwell_psydac now running with --mpi.
- New cobra batch script and cobra install script.
- Move mpi initialization to exec.py.
- Added new code "inverse_mass_test" + profiler for scaling tests.
- Added the profiler in the command line. This provides an easy-to-use scaling analysis for mpi.