Dear R-help members, To whom it may concern, our research group is conducting a study to evaluate the predictive value of 24 hour blood pressure variability. We are looking for an R routine that performs a fast Fourier transform spectral analysis (with an output of the approximation function of the Fourier and estimates the validity of the model for the various harmonics). Thanks Vittorio Colagrande [[alternative HTML version deleted]]
Have you done any homework. help.search() or ... spectrum will produce a spectrum and fft is the underlying function. On Fri, Mar 13, 2009 at 2:46 PM, Vittorio Colagrande <colavittorio at virgilio.it> wrote:> Dear R-help members, > > To whom it may concern, our research group is conducting a study to evaluate the predictive > value of 24 hour blood pressure variability. > We are looking for an R routine that performs a fast Fourier transform spectral analysis > (with an output of the approximation function of the Fourier and estimates the validity > of the model for the various harmonics). > Thanks > Vittorio Colagrande > ? ? ? ?[[alternative HTML version deleted]] > > ______________________________________________ > R-help at r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code. >-- Stephen Sefick Let's not spend our time and resources thinking about things that are so little or so large that all they really do for us is puff us up and make us feel like gods. We are mammals, and have not exhausted the annoying little problems of being mammals. -K. Mullis
Just a word of caution. Having done a lot of work with 24 hour blood pressure and ecg recordings, these series are seldom stationary which presents problems with spectral analysis. I don't know what your ultimate goal is, but in my work I found it often better to work with subsets, of the series, chosen according to the needs of the study. There is an extensive literature, on this type of study. If you haven't done so, I encourage you to do a literature search. Murray ----- Original Message ----- From: "Vittorio Colagrande" <colavittorio at virgilio.it> To: <r-help at r-project.org> Sent: Friday, March 13, 2009 2:46 PM Subject: [R] Fourier Analysis Help> Dear R-help members, > > To whom it may concern, our research group is conducting a study to > evaluate the predictive > value of 24 hour blood pressure variability. > We are looking for an R routine that performs a fast Fourier transform > spectral analysis > (with an output of the approximation function of the Fourier and estimates > the validity > of the model for the various harmonics). > Thanks > Vittorio Colagrande > [[alternative HTML version deleted]] > > ______________________________________________ > R-help at r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide > http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code. >