Added a how-to on the Nuclear option.
@@ -103,3 +103,33 @@ This may take some time to run in its entirety. If you changed the API, you may
have to modify the tests to account for this. You should also add your own
tests for any new functions or behaviors that were added.
+
+Occasionally, modifications made correctly as described above will still not function properly.
+This is because python installation files are not being properly overwritten, and
+the interpreter is getting confused which version to use. At this point it is often best to resort
+to the "nuclear option" of deleting all python files related to pyccl and starting from
+scratch. The procedure is as follows:
+1. Run clean scripts
+
+1.1 Execute `make clean`
+
+1.2 Execute `python setup.py clean`
+
+2. Delete installed python files
+
+2.1 Execute `rm -r build/`, deleting the python build directory
+
+2.2 Execute `rm pyccl/ccl_wrap.c pyccl/ccllib.py`, deleting the autogenerated swig files
+
+2.3 Check your `~/.local/` directory for any pyccl files, and delete them.
+
+2.4 Similarly for files in your `/usr/lib/` and `/usr/local/lib`
+
+2.5 Still not working? You can exectute `python setup.py install [args] --record files.txt`.
+`files.txt` will have a list of all files written when calling the install script with
+arguments `args`. Perhaps there are files somwhere else on your system!
+
+3. You can now reinstall the package in the normal way, starting with the
+C code and then the python code.
+
+
