I have a PDF from a paper. (tandfonline.com/doi/abs/10.1080/03610920008832632#.U9FTD_ldUcC) and I wrote a implementation in python. however, it dose not have the same shape as a histogram of synthetic data. cross validated the right place to ask about this?

Definitely on topic @Jacob - just make sure to try to reduce the problem to be very specific. A dump of a ton of code is unlikely to generate much help (I realize it can be difficult though to reduce it down in many situations though).

A belated thank you for the reference @whuber and @gung!