LAPACK Archives

[Lapack] Lapack bug -- dgelsd/dlascl hangs

[I think this one didn't make it through the first time, so I re-send it
here]

We are mostly users of dgelsd() for fitting data to a model, but
recently I found that the routine hangs for certain input data.

What happens is that in dlals0() the variable diflj is zero and then
cfrom1 in dlascl() is Inf, which means that that routine's exit
criterion is never met.

The matrix has lots of zero entries, but then that is exactly what SVD
should be good at, right?


I have a short test program with a largish (8MB) data file that contains
the corresponding matrix. Should I just e-mail the files to
lapack@Domain.Removed, or do you prefer to download them from a web page?


W o l f g a n g

Version:  3.1.1 (downloaded last week from
http://www.netlib.org/lapack/lapack.tgz)
OS:       Ubuntu 6.06
Compiler: g95, gfortran, g77 (identical problem)
CPU:      Intel 32-bit

--

Wolfgang Dobler
Software Development

JPK Instruments AG
Bouch??str. 12
12435 Berlin, Germany

tel:  +49 30 5331 12070
fax:  +49 30 5331 22555
mail: dobler@Domain.Removed
web:  www.jpk.com, www.spm-workshop.jpk.com

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