Instructions for demos

demos/README.md

+# How to run the demos
+
+## Basic imaging with automatic weighting
+
+- Download the [data](https://www.philipp-arras.de/assets/CYG-ALL-2052-2MHZ.ms.tar.gz) and unpack it.
+- Change the path under `[data]` in `cygnusa.cfg` to the path where the data is located.
+- Run
+```sh
+python3 imaging_with_automatic_weighting.py cygnusa.cfg
+```
+or, if you have `mpi4py` installed:
+
+``` sh
+mpirun -np <ntasks> python3 imaging_with_automatic_weighting.py cygnusa.cfg
+```
+which should speed up the computation. The number of threads used *per task* can be set in the configuration file `cygnusa.cfg` in the section `[technical]/nthreads`. The number threads multiplied by the number of MPI tasks should not exceed the number CPU cores available on the machine.