On Fri, 24 Aug 2007, Julien Langou wrote:
4- If the matrix is ill-conditioned ....
....... They will filter the small singular values out of your
initial matrix A, once those are removed your system becomes overdetermined
and we solve a least squares problem on it. Those routines are ZGELSY (QR
with column pivoting), ZGELSD (SVD with Divide and Conquer), ZGELSS (SVD with
That what I was afraid ZGELS will silently do for me...
But now from your explanation I understood such an algorithm has a
different driver routine .