How to fit an ex-wald distribution model with R? I'm working on reaction time data. I want to fit the data with an ex-wald model but I only found one paper which interpreted the fitting with S. But I don't know S. Are there any ways to fit the RT data with R, python or Matlab?
This seems promising. I haven't used it

Heathcote, A. (2004). Fitting Wald and ex-Wald distributions to response time data: An example using functions for the S-PLUS package. Behavior Research Methods, Instruments, &amp; Computers, 36(4), 678-694.
http://www.tascl.org/uploads/4/9/3/3/49339445/26_.pdf

It does include s-plus code in a supplement to the journal article:
https://link.springer.com/article/10.3758%2FBF03206550

Often S-plus can be used in R, sometimes with some adjustments.