DGELSx: variables A and B unchanged

[edita87]

I am trying to solve a linear least squares problem using LAPACK's specialized routines. Right after DGELS returns, the variables A and B are unchanged but info evaluates to 0. I am using PGI Fortran 7.2-5 with BLAS and LAPACK as released by PGI, on a Dell Precision T7400.

Has anyone else experienced this problem? Is there something I am not doing right? I even tried for a simple 2x2 matrix but the outcome was the same: A and B had the same value as before entering DGELS

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Code: Select all

call DGELS(tr, 2, 2, 1, amat, 2, bvec, 2, ym, -1, infols)

Code: Select all

[alexgc@predeal SWE_NEW]$ ./sensobs
 RHS before
    1.000000000000000         1.000000000000000     
    1.000000000000000        -1.000000000000000     
 LHS before
    1.000000000000000     
    0.000000000000000     
 info (as returned by DGELS) =             0
 RHS after <=> factorization
    1.000000000000000         1.000000000000000     
    1.000000000000000        -1.000000000000000     
 LHS after <=> solution
    1.000000000000000     
    0.000000000000000     
FORTRAN STOP