Package now uses registration for native (C) routines.
For determining the concentration parameters the additional method "Song_et_al_2012" was added which performs 2 Halley steps.
A vignette documenting the use of the package and some implementation issues is added.
A() and the functions of its first and second
derivative now use the Taylor series expansion for small values of
A() modified to have now three methods
"PCF": Perron continued fraction,
"RH": using a ratio of generalized
hypergeometric series). By default, method
"PCF" is used.
The random initializations for multiple runs are now determined within the loop separately for each run.