math/R-cran-numDeriv 2016.8.1.1_3 DragonFly

Methods for calculating (usually) accurate numerical first and second order derivatives. Accurate calculations are done using 'Richardson"s' extrapolation or, when applicable, a complex step derivative is available. A simple difference method is also provided. Simple difference is (usually) less accurate but is much quicker than 'Richardson"s' extrapolation and provides a useful cross-check. Methods are provided for real scalar and vector valued functions.