Fast Implementation of the Diffusion Decision Model

Provides the probability density function (PDF) and cumulative distribution function (CDF) of the diffusion decision model (DDM; e.g., Ratcliff & McKoon, 2008, ) with across-trial variability in the drift rate. Because the PDF and CDF of the DDM both contain an infinite sum, they needs to be approximated. 'fddm' implements all published approximations (Navarro & Fuss, 2009, ; Gondan, Blurton, & Kesselmeier, 2014, ; Blurton, Kesselmeier, & Gondan, 2017, ) plus new approximations. All approximations are implemented purely in 'C++' providing faster speed than existing packages.