As far as I know the Aniline point is a measure of the aromatics content of a petroleum fraction. The laboratory method is to take a 50-50 volumetric mix of the sample and aniline, and heat the mixture. The temperature at which the mixture becomes homogenous completely is the Aniline point of that sample. eg the aniline point of HSD is 78 deg. C. also it is is an input in the equation for Diesel Index. I dont think anilinepoint can be calculated by formula, it is a by analytical method.
For further details pl refere to Nelson's handbook on refinery proceses or any other std text book on refining.