nleqslv from the findRoots(beta.init, eq.func, d.eq.func = NULL, arg.list, ...)beta should be a vector over which the zeros are sought and
the second argument arg.list a list of additional arguments.eq.func taking the same
arguments as eq.func. Supplying this function can speed up
calculations. Default is NULL.eq.func and d.eq.funcnleqslveq.func.nleqslv.findRoots calculates zeros fo the function eq.func
and is meant to be called from ebeFit and
drFit. It is the default equation solving function
in drgee. It is supplied as a separate function in order
to allow users to use other equation solvers by writing their
own wrapper with the same interface as findRoots.nleqslv in package ebeFit, drFit.