ffd is a MATLAB toolbox that implements the factored form descent algorithm, the original form of which was described in [1]. It can be used to retrieve the spatial coherence statistics of a quasi-monochromatic source given known optical system(s) and measured point-wise intensity values of the output of said field through said optical system(s).
Add the directory containing ffd.m to MATLAB's path using addpath or something similar. Make sure the entire directory structure is the same as the repository (e.g. +ffd directories are present, etc.). Run the provided sample code to test your installation:
>> ffd.sample.run- Z. Zhang, Z. Chen, S. Rehman, and G. Barbastathis, "Factored form descent: a practical algorithm for coherence retrieval," Opt. Express 21, 5759--5780 (2013)