[Rd] eigen returns NAs from a real matrix

[Martin Maechler]

>>>>> "Duncan" == Duncan Murdoch <murdoch at stats.uwo.ca>
>>>>>     on Mon, 19 Mar 2007 09:01:39 -0400 writes:

    Duncan> On 3/19/2007 6:48 AM, Martin Maechler wrote:
    >>>>>>> "BDR" == Prof Brian Ripley <ripley at stats.ox.ac.uk>
    >>>>>>> on Sun, 18 Mar 2007 06:51:58 +0000 (GMT) writes:
    >> 
    BDR> On Sat, 17 Mar 2007, Spencer Graves wrote:
    >> >> Hi, All:
    >> >> Attached please find a symmetric, indefinite matrix for which 
    >> >> 'eigen(...)$vectors' included NAs: 
    >> >>> load("eigenBug.Rdata")
    >> >>> sum(is.na(eigen(eigenBug)$vectors))
    >> >> [1] 5670
    >> >>> sessioninfo()
    >> >> Error: could not find function "sessioninfo"
    >> >>> sessionInfo()
    >> >> R version 2.4.1 (2006-12-18)
    >> >> i386-pc-mingw32
    >> >> 
    >> >> locale:
    >> >> LC_COLLATE=English_United States.1252;LC_CTYPE=English_United 
    >> >> States.1252;LC_MONETARY=English_United 
    >> >> States.1252;LC_NUMERIC=C;LC_TIME=English_United States.1252
    >> >> 
    >> >> attached base packages:
    >> >> [1] "stats"     "graphics"  "grDevices" "utils"     "datasets"  "methods" [7] 
    >> >> "base"
    >> >> Using EISPACK does NOT return NAs: > sum(is.na(eigen(eigenBug, 
    >> >> EISPACK=TRUE)$vectors))
    >> >> [1] 0
    >> >> 
    >> >> 
    >> >> I traced the problem to the following line in 'eigen':
    >> >> z <- if (!complex.x)
    >> >> .Call("La_rs", x, only.values, PACKAGE = "base")
    >> >> 
    >> >> 
    >> >> Comments?
    >> 
    BDR> Nothing appeared as an attachment.
    >> 
    >> it was a zip file which is not among the allowed ones
    >> (.tar.gz / *.tgz  would work).
    >> 
    >> Spencer has also contacted me in private,
    >> so you now can use something like :
    >> 
    >> F <- tempfile()
    >> download.file("ftp://stat.ethz.ch/U/maechler/R/eigenBug.Rdata", F)
    >> load(F)

    Duncan> This is unrelated to Spencer's problem, but this
    Duncan> sequence failed for me.

    Duncan> By default it will treat the file as a text file,
    Duncan> and convert EOL markers for Windows.  Adding
    Duncan> "mode='wb'" to the download.file() call is necessary.

ok;  Thank you, Duncan.

{For me, that's yet another reason why I think it would be  ``nice''
 if both  load() and source()  would work with general
 connections the same way as read.table(), and I could just say

     load("ftp://stat.ethz.ch/U/maechler/R/eigenBug.Rdata")
}

    >> str(eigenBug)# tons of dinames; get rid of them:
    >> M <- unname(eigenBug)
    >> 
    >> sum(is.na(eigen(M)$vectors))
    >> # 0 (for MM, on Linux);  '5670' for Spencer

    Duncan> I get the same as Spencer in 2.4.1, but zero in
    Duncan> R-devel, in Windows. 

ahh, that's good news.

Maybe Spencer could install a revcent version R-devel on his
Windows machine, and try the example?


    Duncan> I haven't tried R-patched yet: there were network
    Duncan> problems here this morning, and the build failed.

    Duncan> Duncan Murdoch

    >> sum(is.na(eigen(M, EISPACK=TRUE)$vectors))
    >> # 0
    >> 
    >> ## Guess about what kind of BLAS/Lapack I'm using :
    >> file.info(list.files(R.home("lib"), full=TRUE))[,1:3]
    >> ##                                        size isdir mode
    >> ## ....64-linux-inst/lib/libRblas.so    422558 FALSE  755
    >> ## ....64-linux-inst/lib/libRlapack.so 3144596 FALSE  755
    >> 
    >> 
    >> I.e. I don't get any NA's
    >> which shows to me that the bug is most probably in the Lapack -
    >> Version that Spencer's version of R is linked against.
    >> 
    >> Martin Maechler, ETH Zurich