= [ PAGE BEING BUILT ] =

= Usage Examples =
This wiki outlines some potential usages for NUISANCE.

If you haven't yet build the framework, do so [https://nuisance.hepforge.org/nuisanceinstallation.html here].


== The card file ==
NUISANCE requires the user providing an input card file which species:

 * The data sample(s) to compare to 
 * The generators and their file locations
 * Any additional parameters that a sample might take (optional)
 * A normalisation factor to apply uniformly to the MC (optional)

When the generator provides a reweighting interface, systematic parameters to reweight or fit can be provided. To do this we need:

 * Name of the systematic parameter in the reweighting engine
 * Current value of the parameter
 * Minimum value of the parameter (optional)
 * Maximum value of the parameter (optional)
 * Starting value of the parameter (optional)
 * Whether we `FIX` or `FREE` the parameter

All NUISANCE executables run based on the card file, except for when producing generator flat trees. 

= Comparisons =

= Tuning =

Use the `nuisfit` executable for tuning. 

The default fitter is `ROOT`'s `MIGRAD` algorithm with hard limits. The executable accepts `-f` to change this behaviour. 

The accepted arguments are specified in `src/Routines/MinimizerRoutines.cxx` and NUISANCE accepts all the currently implemented minimisations in ROOT::Minimizer. 

{{{
#!div class="code"

  fAllowedRoutines = ("Migrad,Simplex,Combined,"
                      "Brute,Fumili,ConjugateFR,"
                      "ConjugatePR,BFGS,BFGS2,"
                      "SteepDesc,GSLSimAn,FixAtLim,FixAtLimBreak"
                      "Chi2Scan1D,Chi2Scan2D,Contours,ErrorBands");
}}}

Separating options with commas runs them in order, e.g. `-f Simplex,Combined` will first run a `Simplex` minimisation and then propagate those results to a `Combined` minimisation. 

= Making a flat-tree from the generators =