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[Lapack] [lapackers] Fwd: Incorrect R/C description in LAPACK 3.2.1 *ger

I agree that the comments are buggy, because they were copied
in toto from the calling routine, sgesvxx, for which they are accurate,
without changing them appropriately. Thanks for finding this!

I guess we need test code for our comments...

Julie, the same error occurs in the other data types.
Here is a prototype fix for single, which should be easy to convert:

For R:
   Change description from "(input or output)" to "(input)"
   Remove sentences: R is an input argument if FACT = 'F'; otherwise,
                                 R is an output argument. If FACT = 'F' and
                                 EQUED = 'R' or 'B', each element of R 
must be positive.
                                 If R is output, each element of R must 
be positive.
   Change next sentence, starting "If R is input ...", to start "If R is 
accessed..."

For C:
   Change description from "(input or output)" to "(input)"
   Remove sentences: C is an input argument if FACT = 'F'; otherwise,
                                 C is an output argument. If FACT = 'F' and
                                 EQUED = 'R' or 'B', each element of C 
must be positive.
                                 If C is output, each element of C must 
be positive.
   Change next sentence, starting "If C is input ...", to start "If C is 
accessed..." 

Thanks,
Jim

julie langou wrote:
Dear Jim,
Intel is reporting some comment issue in  *gerfsx.f.
I did a quick check and I believe the comments need a substantial change.
Would you or a student mind taking a look at them and provide a fix, 
please?
Regards
Julie
Begin forwarded message:

*From: *"Chuvelev, Michael" <michael.chuvelev@Domain.Removed 
<mailto:michael.chuvelev@Domain.Removed>>
*Date: *March 1, 2010 3:42:55 AM MST
*To: *"lapack@Domain.Removed <mailto:lapack@Domain.Removed>" 
<lapack@Domain.Removed <mailto:lapack@Domain.Removed>>
*Cc: *"Koldakov, Vladimir V" <vladimir.v.koldakov@Domain.Removed 
<mailto:vladimir.v.koldakov@Domain.Removed>>, "Kobotov, Alexander V" 
<alexander.v.kobotov@Domain.Removed 
<mailto:alexander.v.kobotov@Domain.Removed>>
*Subject: **[Lapack] Incorrect R/C description in LAPACK 3.2.1 *gerfsx.f*

Dear LAPACKers,
 
the R/C parameter description for the routines *gerfsx seems to be 
incorrect:
 
*     R       (input or output) REAL array, dimension (N)
*     The row scale factors for A.  If EQUED = 'R' or 'B', A is
*     multiplied on the left by diag(R); if EQUED = 'N' or 'C', R
*     is not accessed.  R is an input argument if FACT = 'F';
*     otherwise, R is an output argument.  If FACT = 'F' and
*     EQUED = 'R' or 'B', each element of R must be positive.
*     If R is output, each element of R is a power of the radix.
*     If R is input, each element of R should be a power of the radix
*     to ensure a reliable solution and error estimates. Scaling by
*     powers of the radix does not cause rounding errors unless the
*     result underflows or overflows. Rounding errors during scaling
*     lead to refining with a matrix that is not equivalent to the
*     input matrix, producing error estimates that may not be
*     reliable.
 
1) R/C are input only by their usage,
2) there's no FACT parameter in these routines
 
Thanks.
 
Best regards,
 
Michael.
 
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**********************************************
Julie Langou; Research Associate in Computer Science
Innovative Computing Laboratory;
University of Tennessee from Denver, Colorado ;-)
julie@Domain.Removed 
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