Please report problems in the code to the package maintainer (CCing).
Best,
Uwe Ligges
Mikhail Titov wrote:
Hello!
I tried to contact author of the package, but I got no reply. That is why I
write it here. This might be useful for those who were using cts for spectral
analysis of non-uniformly spaced data.
In file spec.ls.R from cts_1.0-1.tar.gz lines 59-60 are written as
pgram[k, i, j] <- 0.5 * ((sum(x[1:length(ti)]* cos(2 * pi * freq.temp[k] * (ti - tao))))^2/sum((cos(2 *
pi * freq.temp[k] * (ti - tao)))^2) + (sum(x[1:length(ti)] * sin(2 * pi * freq.temp[k] * (ti - tao))))^2 ===> ) <=== /sum((sin(2 * pi * freq.temp[k] * (ti - tao)))^2)
Is there a misplaced bracket (shown like ===> ) <===)? Should it be like the
following?
pgram[k, i, j] <- 0.5 * ((sum(x[1:length(ti)]* cos(2 * pi * freq.temp[k] * (ti - tao))))^2/sum((cos(2 *
pi * freq.temp[k] * (ti - tao)))^2) + (sum(x[1:length(ti)] * sin(2 * pi * freq.temp[k] * (ti - tao))))^2/sum((sin(2 * pi * freq.temp[k] * (ti - tao)))^2) ===> ) <===
Here is quick reference
http://en.wikipedia.org/wiki/Least-squares_spectral_analysis#The_Lomb.E2.80.93Scargle_periodogram
. One half coefficient was not applied to entire expression.
Also I find weird next lines (61-62)
pgram[1, i, j] <- 0.5 * (pgram[2, i, j] + pgram[N, i, j])
First of all, such things should not be in the for loop. Second, I don't quite
understand the meaning of it.
P.S. Should I use tapering of my data? If I just try to fit sine and cosine, I
may not use it, however for FFT windowing is a must. What about Lomb-Scargle?
Mikhail
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