Generate the square wave: genseq <- function() { x <- numeric(4*365) s <- seq(as.Date("2005-01-01"), as.Date("2008-12-31"), by="month") ob <- as.vector(s[c(10,22,34,46)] - as.Date("2005-01-01")) oe <- as.vector(s[c(11,23,35,47)] - as.Date("2005-01-01")) for(.index in 1:length(ob)) { x[ob[.index]:(oe[.index] - 1)] <- 1 } return(ts(x, frequency=365)) }
Take the fft of the series generated: series <- genseq() series <- ts(c(series, rep(0, nextn(length(series)) - length(series))), frequency = 365) fs <- fft(series) Filter the response. Pick any two frequencies: ff <- complex(length(fs)) ff[9] <- fs[9] ff[5] <- fs[5] Include the DC component: ff[1] <- fs[1] Take the inverse fi <- fft(ff, inverse=TRUE) / length(ff) Plot plot(fi) Notice that the plot is the Re vs. Im on the x and y axis' respectively. Now notice the difference if I plot the inverse fft plot(fft(fs/length(fs), inverse=TRUE)) My question was simply the "automatic" mode that 'plot' seems to be taking. In the first instance Re vs. Im and the second series vs. Time. Kevin ---- Dieter Menne <[EMAIL PROTECTED]> wrote: > <rkevinburton <at> charter.net> writes: > > > > > So iis what you are saying n plotting the list of compliex numbers 'R' > recognizes the non-symmery and plots > > it differently (Re vs. Im) rather than versus Time? > > Mmm... don't fully understand what you mean, mainly because your program > example > did not run and I had do some guessing what your problem was. > > Dieter > > ______________________________________________ > R-help@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. ______________________________________________ R-help@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.