[R] how to get higher derivatives with "deriv"
Wu Gong
wg2f at mtmail.mtsu.edu
Thu Jul 29 23:27:59 CEST 2010
## specify the function string
f.str <- "x^alpha"
## higher derivatives
DD <- function(f.str, x = 2, alpha=3,order = 1){
expr.s <- parse(text=f.str)
while(order>=1) {
expr.s <- D(expr.s,"x")
order <- order-1}
eval(expr.s)
}
compute
DD(f.str,x=1,alpha=0.5,order=1)
-----
A R learner.
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