Displaying 3 results from an estimated 3 matches for "vetterl".
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vetter
2005 Nov 03
1
Real FFT
The book "Numerical Recipes in Fortran77" by Press, Teukolsky, Vetterling and Flannery describes a way to "pack" the even and odd coordinates of a real vector "R" into a complex vector "C" of half the length. Then using various FFT symmetries, they extract the FFT of "R" from the FFT of "C" which is half the length of...
2004 Sep 15
6
Bessel function
Dear all
Currently, I'm implementing the generalized hyperbolic distribution into
Splus. Unfortunately the Bessel function is not implemented in Splus. In
R the Bessel function does exist but it is an internal function and I'm
not able to look at the code.
Is there any possibility to see the code of the Bessel function in R or
does anybody has an implementation of the Bessel function in
2012 Apr 23
2
automating a script to read a file
...t;skewtitle>)")
flush.console()
# sample input data could be the following:
# -100, 1000, 976.02, 230, -34, 0.7543
# 0, 500, 270, 350, -13, 0.7707
# or any other data of similar form
erf <- function(z) {
## Chebyshev fitting formula for erf(z) from
## Vetterling, W.T., , W.H. Press, S.A. Teukolsky, and B.P.
Flannery. 1999.
## Numerical Recipes: Example Book [C], Second Edition.
## Cambridge University Press, NY. , Chapter 6-2.
t <- 1.0/(1.0 + 0.5 * abs(z))
## use Horner's method
ans <- (1 - t * exp(-z * z...