A global non-analytical fit method for the complex lineshape analysis of Bi$_2$Sr$_2$CaCu$_2$O$_{8+\delta}$
The implementation of global non-analytical fit is exemplified by its application to the spectral analysis of the complex lineshape of Bi$_2$Sr$_2$CaCu$_2$O$_{8+\delta}$ at $(\pi,0)$. It deals with properly a multi-level globality in the fitting parameters and efficiently the non-analytical evaluation of the fitting function, thus exhibiting a potential applicability to a wide range of systematic analysis task.