Re: [R] fft: characteristic function to distribution

2008-05-13 Thread Thomas Steiner
Matthias Kohl was so kind and provided me the following lines in this issue: library(distrEx) chf <- function(t, D){ E(D, function(x){exp(1i*t*x)}, useApply = FALSE) } ## Normalverteilung D <- Norm() t <- seq(-3, 3, by = 0.05) chf.norm <- sapply(t, chf, D = D) chf.exakt <- exp(-t^2/2) chf.diff

Re: [R] fft: characteristic function to distribution

2008-05-07 Thread Thomas Steiner
Thank you Prof Ripley for your answer. > > The characteristic function is the inverse Fourier transform of the > > distribution function. The characteristic function of a normaly > > distributed random variable is exp(-t^2/2). > > > > The fft is a discrete Fourier transforn, not a continuous one.

Re: [R] fft: characteristic function to distribution

2008-04-30 Thread Prof Brian Ripley
On Wed, 30 Apr 2008, Thomas Steiner wrote: The characteristic function is the inverse Fourier transform of the distribution function. The characteristic function of a normaly distributed random variable is exp(-t^2/2). The fft is a discrete Fourier transforn, not a continuous one. Further in e