Description 
We present methods for calculating the risk neutral density for several financial models. We consider:
Black, Displaced Diffusion, CEV, SABR, Heston, Bates, HullWhite, HestonHullWhite, VG, NIG, CGMY, VGGOU, VGCIR, NIGCIR, NIGGOU.
For models where no analytic representation of the density is available we either use approximation formulae or methods based on fourier transform.
We study the effects of changing the model parameters. This illustrates the topics from chapters 2 and 3 of the book Financial Modelling  Theory, Implementation and Practice.
We provide scripts for testin each model and plot the densities.
