The code uses two approaches to fit the experimental data with gamma distribution . 

1) find a0 + a2*P2 + a4*P4, then use a0 to search for mini delta, the mixing ratio
2) fit the a0, delta, and sigma simultaniously.

#simply make to compile the ad++.cpp

The settings and data are hard coded.

#or, using root, load ad++.h as macro