Updated readme to mention response_fn

README.md

@@ -10,6 +10,10 @@ That is, if you learn methods by reading code, like I do.
 It uses the full preconditioning method of Rybicki & Hummer (1992) with the ability to handle overlapping transitions, but under the assumption of complete redistribution.
 The formal solver is currently using simple piecewise linear short characteristics due to its simplicity and the pedagogic benefits thereof. 
 
+The slides for the associated talk are in the Slides directory.
+
+In the file `response_fn.py` there is a simple example of computing the NLTE response function for CaII 8542, admittedly in a very crude and slow way (it will take multiple minutes to run). I recommend just running the synthesis in `example.py` first for familiarity with the code.
+
 ### DIY
 
 If you want to have a go at implementing the MALI method, then the `formal_sol_gamma_matrices` and `uv` functions in `rh_method.py` have been left documented but not complete on the `DIY` branch. It would also be an interesting exercise to extend the formal solver to use the monotonic piecewise parabolic method of Auer & Paletou (1994).