[Rd] cmdscale in package mva (PR#1027)

[ripley@stats.ox.ac.uk]

On Tue, 17 Jul 2001, Kurt Hornik wrote:

> >>>>> laurent  writes:
>
> > Full_Name: Laurent Gautier
> > Version: 1.3.0-patched
> > OS: IRIX 6.5
> > Submission from: (NULL) (130.225.67.199)
>
>
> > Hello,
>
> > The function La.eigen, called by cmdscale in the package mva behaves
> > an unexplicable way (for me).
>
> > The following lines show what happened.  I tried the very same on
> > linux, and it worked fine.
>
> >> a <- matrix(c(1,2,3,2),3,3)
> >> a
> >      [,1] [,2] [,3]
> > [1,]    1    2    3
> > [2,]    2    1    2
> > [3,]    3    2    1
> >> library(mva)
> >> cmdscale(a)
> > Error in La.eigen(Tmat, symmetric = TRUE) :
> > 	On entry to DSYEV  parameter number 8 had an illegal value
>
> I can confirm this on Naras's IRIX machine (in fact, was just about to
> report this myself ...)

Can you put a breakpoint at line 72 of Lapack.c and see what value of lwork
is returned?  Alternatively, it may fail on the first dsyev call, in which
case I would guess that the wrong LAPACK routine is being found (and that's
a plausible explanation).

I get 102 with the built-in BLAS: the answer should be at least max(1, 3*n-1)

What BLAS is in use?  The intention is that the workspace is chosen large
enough to allow the BLAS to work efficiently: it might just be that
the BLAS is reporting erroneously.

-- 
Brian D. Ripley,                  ripley@stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
1 South Parks Road,                     +44 1865 272860 (secr)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595


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