[Rd] xerbla called from BLAS routine (PR#8100)

[Göran Broström]

On Mon, Aug 29, 2005 at 10:27:24AM +0100, Prof Brian Ripley wrote:
> On Mon, 29 Aug 2005, Göran Broström wrote:
[...]
> >
> >BTW, the original BLAS xerbla (from the netlib page you referred to)
> >gives the message:
> >
> >    WRITE( *, FMT = 9999 )SRNAME, INFO
> >9999 FORMAT( ' ** On entry to ', A6, ' parameter number ', I2, ' had ',
> >    $      'an illegal value' )
> >
> >which I think is even better than my original suggestion.
> >(Why was it changed?)
> 
> Probably because R is not a Fortran program and so needs to make clear 
> what these refer to, and because LAPACK does have other error values that 
> invalid parameter values.

LAPACK/BLAS routines call xerbla "if an input parameter has an 
invalid value" (exact quote from  XERBLA at Netlib). Other types of errors 
are not printed (by xerbla), but it is up to the user to check the return 
value of the argument 'INFO'. See
http://www.netlib.org/lapack/lug/node119.html.

So we can safely give the more informative, original, error messages, 
together with mentioning LAPACK and eventually BLAS, whatever you prefer.
This would "make clear what these refer to". Given that other BLAS/LAPACK 
routines than xerbla aren't changed in R, of course.

Göran