demo/Ryacas-Function.R

In ggrothendieck/ryacas: R Interface to the 'Yacas' Computer Algebra System

# construct an R function for the Burr probability density
# function (PDF) given the Burr cumulative distribution function (CDF)
BurrCDF <- function(x, c = 1, k = 1) 1-(1+x^c)^-k

# transfer CDF to yacas
yacas(BurrCDF)

# create a template for the PDF from the CDF
BurrPDF <- BurrCDF

# differentiate CDF and place resulting expression in body
body(BurrPDF) <- yacas(expression(deriv(BurrCDF(x,c,k))))[[1]]

# test out PDF
BurrPDF(1)