Thanks, I will look at that. -Roy
> On May 27, 2015, at 9:15 AM, Prof Brian Ripley <rip...@stats.ox.ac.uk> wrote: > > On 27/05/2015 16:54, Roy Mendelssohn - NOAA Federal wrote: >> Hi All: >> >> Is there a routine in R that allows me to simulate a time series that has a >> given spectrum? I have looked at the R Time Series Task view, and have done >> a web search also, including an article to appear in the handbook of >> statistics on time series in R, but I don’t see anything offhand. There are >> some that will simulate state-space models or for given covariances >> matrices, but for a variety of reasons I would prefer simulating series with >> a given spectrum. > > It is relatively simple to do for series of lengths a power of two (and you > can simulate a longer series to achieve this). Use the spectrum values to > simulate independent complex normals with uniform phase and variance > proportional to the spectral density at the Fourier frequencies then use the > inverse fft() to get the series. > > You should be able to copy some code from boot::tsboot()'s 'scramble' method. > >> Thanks for any help. >> >> -Roy >> >> >> ********************** >> "The contents of this message do not reflect any position of the U.S. >> Government or NOAA." >> ********************** >> Roy Mendelssohn >> Supervisory Operations Research Analyst >> NOAA/NMFS >> Environmental Research Division >> Southwest Fisheries Science Center >> ***Note new address and phone*** >> 110 Shaffer Road >> Santa Cruz, CA 95060 >> Phone: (831)-420-3666 >> Fax: (831) 420-3980 >> e-mail: roy.mendelss...@noaa.gov www: http://www.pfeg.noaa.gov/ > > > -- > Brian D. Ripley, rip...@stats.ox.ac.uk > Emeritus Professor of Applied Statistics, University of Oxford > 1 South Parks Road, Oxford OX1 3TG, UK ********************** "The contents of this message do not reflect any position of the U.S. Government or NOAA." ********************** Roy Mendelssohn Supervisory Operations Research Analyst NOAA/NMFS Environmental Research Division Southwest Fisheries Science Center ***Note new address and phone*** 110 Shaffer Road Santa Cruz, CA 95060 Phone: (831)-420-3666 Fax: (831) 420-3980 e-mail: roy.mendelss...@noaa.gov www: http://www.pfeg.noaa.gov/ "Old age and treachery will overcome youth and skill." "From those who have been given much, much will be expected" "the arc of the moral universe is long, but it bends toward justice" -MLK Jr. ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see 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.
