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[Lapack] issue with DGGSVD in LAPACK

Thank you very much for your reply.

Regarding your previous email, the reason I chose CLAPACK is because 
I know it best.  I have very limited experience with fortran in 
general and I have not looked into MKL.

I am using the native BLAS that came with the CLAPACK 
distribution, which works on my local machine using gcc, but I want 
to get it running on a larger platform and uses icc.  The larger 
platform has ATLAS BLAS which I hope to use in the future.  I would 
also like to get this running in a parallel cluster because I am 
dealing with very large matrices and require a few hundred singular 

As for the error, I run the exact same code on my local machine (with 
gcc) and it works perfectly.

I will try your suggested flags and thanks again for looking into it.

At 7:22 AM -0600 7/9/09, julie langou wrote:
Icc is a picky compiler. Usually we use the following 
flags,-fltconsistency -fp_port
I am not sure this will help much anyway...
Which BLAS library are you using? MKL?
and which LAPACK (c version)? CLAPACK 3.2.1?
I will try to reproduce your problem .

Regarding the error code, if INFO =-4, he is complaining about the 
parameter N.
     $                   WORK, LWORK, INFO )
In the code, we are just making sure N is greater than 0.
Maybe you put L in place of N, no?.
      ELSE IF( N.LT.0 ) THEN
         INFO = -4


On Jul 8, 2009, at 11:45 AM, Eric Loomis wrote:

Hello, I ran into a problem building the LAPACK (c version) on a 
high performance computing platform using an icc compiler.  The 
libraries seemed to build okay, but when I ran the testing 
executables I ran into some errors in the SVD routine.  I have 
attached the output file with the errors.  Do you know what may 
have caused these errors?

I have probably a related problem when I try to run some of my code 
using the DGESVD routine in that I get an error
** On entry to DGESVD, parameter number  4 had an illegal value

INFO = -4
LWORK = -1

Can you help me with any of these issues?


At 10:21 AM -0700 6/25/09, Zhaojun Bai wrote:

Hi Eric,

I would be happy to try to help out here. Can you let me

the exact formulation of the constrained LS

problem you want to solver? I can take a look and

see whether we're on the right-track to use the DGGSVD

from LAPACK.

Apologize the delay for response. We just finished the spring

quarter term.


Zhaojun Bai

UC Davis

Eric Loomis wrote:


I am using the routine DGGSVD (CLAPACK) to solve constrained 
least squares problems.  To do this I need to form a matrix X 
from Q and R as discussed in GSVD literature.  R appears to be 
nearly diagonal. The result of using the GSVD to solve a system 
of equations is that the first half of the solution is nearly 
zero, but the second half gives the correct answer.  Can you put 
me in contact with someone familiar with this routine to work out 
this issue?  I can supply the source code if required.

Eric Loomis
P-24 plasma physics
Los Alamos National Laboratory
mailstop E526
Lapack mailing list

Julie Langou; Research Associate in Computer Science
Innovative Computing Laboratory;
University of Tennessee from Denver, Colorado ;-)

Eric Loomis
P-24 plasma physics
Los Alamos National Laboratory
mailstop E526
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