Dear all, I found the following behaviour with pacf() in the multivariate case,
set.seed(10) x <- rnorm(1000,sd=10000) y <- rnorm(1000,sd=1) pacf(ts(cbind(x,y)),plot=FALSE,lag.max=10) Partial autocorrelations of series 'cbind(x, y)', by lag , , x x y 0.047 ( 1) 0.000 ( -1) 0.011 ( 2) 0.000 ( -2) 0.005 ( 3) 0.000 ( -3) 0.013 ( 4) 0.000 ( -4) 0.050 ( 5) 0.000 ( -5) 0.034 ( 6) 0.000 ( -6) 0.026 ( 7) 0.000 ( -7) -0.029 ( 8) 0.000 ( -8) -0.010 ( 9) 0.000 ( -9) -0.013 ( 10) 0.000 (-10) , , y x y 374.052 ( 1) -0.045 ( 1) 66.717 ( 2) -0.024 ( 2) -535.810 ( 3) -0.031 ( 3) 120.802 ( 4) -0.020 ( 4) 142.824 ( 5) 0.004 ( 5) -211.711 ( 6) -0.010 ( 6) 201.856 ( 7) 0.058 ( 7) 286.079 ( 8) -0.035 ( 8) -134.057 ( 9) 0.032 ( 9) -18.200 ( 10) 0.019 ( 10) Since there are multiple ways of defining the pacf for multivariate time series (see e.g. G.C. Reinsel, Elements of multivariate time series analysis, II edition, Springer, section 3.3) and given that in ?pacf there is no reference to articles or books regarding its computation I do not know whether this behaviour is expected or it is a bug instead. In the first case could you provide a reference for it? In the second case I might file a bug report. Thank you for the great work you are doing for the scientific community. kind regards, Simone Giannerini WINDOWS platform i386-pc-mingw32 arch i386 os mingw32 system i386, mingw32 status major 2 minor 5.1 year 2007 month 06 day 27 svn rev 42083 language R version.string R version 2.5.1 (2007-06-27) LINUX > R.Version() $platform [1] "x86_64-unknown-linux-gnu" $arch [1] "x86_64" $os [1] "linux-gnu" $system [1] "x86_64, linux-gnu" $status [1] "" $major [1] "2" $minor [1] "5.1" $year [1] "2007" $month [1] "06" $day [1] "27" $`svn rev` [1] "42083" $language [1] "R" $version.string [1] "R version 2.5.1 (2007-06-27)" -- ______________________________________________________ Simone Giannerini Dipartimento di Scienze Statistiche "Paolo Fortunati" Universita' di Bologna Via delle belle arti 41 - 40126 Bologna, ITALY Tel: +39 051 2098262 Fax: +39 051 232153 ______________________________________________________ [[alternative HTML version deleted]] ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel