merge Reimar's changes

10 jobs for fix_MPI in 8 minutes and 26 seconds (queued for 2 seconds)
Status Job ID Name Coverage
  Build Docker
passed #936692
build_docker_from_cache

00:00:18

 
  Test
passed #936694
test_mpi

00:04:45

passed #936693
test_serial

00:05:23

82.0%
 
  Demo Runs
passed #936699
run_bernoulli

00:00:30

passed #936700
run_curve_fitting

00:00:28

passed #936696
run_getting_started_1

00:00:36

passed #936697
run_getting_started_2

00:01:04

passed #936698
run_getting_started_3

00:02:44

passed #936695
run_ipynb

00:01:31

passed #936701
run_plotting_test

00:00:34