R devel - Aug 2008 - non user-friendly error for chol2inv functions

Hi,

In function chol2inv with the option LINPACK set to false (default), it
raises an error when the matrix is 1x1 matrix (i.e. just a real) saying

'a' must be a numeric matrix

This error is raised by the underlying C function (modLa_chol2inv in
function Lapack.c). Everything is normal, but I wonder if we could have
another behavior when we pass a 1x1 matrix. I spent time this morning
finding where was the error, and it was this "problem".

Thanks in advance

Christophe

	[[alternative HTML version deleted]]

>>>>> "cd" == christophe dutang <dutangc at
gmail.com>
>>>>>     on Fri, 29 Aug 2008 12:44:18 +0200 writes:
    cd> Hi,
    cd> In function chol2inv with the option LINPACK set to false (default),
it
    cd> raises an error when the matrix is 1x1 matrix (i.e. just a real)
saying

    cd> 'a' must be a numeric matrix

It is very helpful, but you have to read and understand it.
I'm pretty sure you did not provide a  1 x 1 matrix.

Here's an example showing how things works :
> m <- matrix(4,1,1)
> cm <- chol(m)
> cm
     [,1]
[1,]    2
> chol2inv(cm)
     [,1]
[1,] 0.25
> 
Martin Maechler, ETH Zurich


    cd> This error is raised by the underlying C function (modLa_chol2inv in
    cd> function Lapack.c). Everything is normal, but I wonder if we could
have
    cd> another behavior when we pass a 1x1 matrix. I spent time this morning
    cd> finding where was the error, and it was this "problem".

    cd> Thanks in advance

    cd> Christophe

    cd> [[alternative HTML version deleted]]

    cd> ______________________________________________
    cd> R-devel at r-project.org mailing list
    cd> https://stat.ethz.ch/mailman/listinfo/r-devel