[R] spec.pgram returns different spectra when fast=TRUE and the number of samples is odd

[Jade Mosley]

Dear all,

This is potentially a bug in spec.pgram, when the number of samples is odd,spec.pgramreturns a different result withfast = TRUE, the example below contains the two varieties with a reference spectrum calculated manually. the number of returned spectra is also larger (50 compared to 49) whenfast = TRUE

x <- rnorm(

99

)
plot(spec.pgram(x, taper =

0

, detrend =

FALSE

, plot =

FALSE

, fast =

FALSE

)$spec, ty =

'l'

)
lines(spec.pgram(x, taper =

0

, detrend =

FALSE

,plot =

FALSE

, fast =

TRUE

)$spec, col =

'red'

)
lines(((abs(fft(x))^

2

)[

2

:

50

])/

99

, col =

'blue'

, lty =

2

)

Best regards
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