Re: [ublas] [bindings] New traits system

Subject: Re: [ublas] [bindings] New traits system
From: Karl Meerbergen (Karl.Meerbergen_at_[hidden])
Date: 2010-01-10 14:09:35

Dear Thomas,

In principle, the e-mail address lapack_at_[hidden] should work, 
otherwise there is LAPACK forum http://icl.cs.utk.edu/lapack-forum/

Best regards,

Karl

Thomas Klimpel wrote:
> Rutger ter Borg wrote:
>   
>> I've made another update to gelsd which hopefully fixes this assertion (it's
>> committed). The regression for gelsd didn't actually pass either, although
>> running the regression showed "*passed*".
>>     
>
> Should be fixed now.
>
>   
>> There's still an issue in the regression for the complex case, which
>> supposedly has an incorrect minimum amount of workspace (LWORK). It matches
>> the documentation, so I am suspecting that the lapack docs isn't correct for
>> LWORK, too.
>>     
>
> I read the fortran code for cgelsd.f to find out the correct minimum value for LWORK. I came to the conclusion that the documentation
>
> *          N and NRHS. As long as LWORK is at least
> *              2 * N + N * NRHS
> *          if M is greater than or equal to N or
> *              2 * M + M * NRHS
> *          if M is less than N, the code will execute correctly.
>
> should be changed to
>
> *          N and NRHS. As long as LWORK is at least
> *              2 * N + N * NRHS
> *          if M is greater than or equal to N or
> *              2 * M + MAX( N, M * NRHS)
> *          if M is less than N, the code will execute correctly.
>
> I changed the template for gelsd.hpp accordingly, and the regression tests passes now.
>
> Should we create patches for the "bugs" in the lapack documentation?
>
> Regards,
> Thomas
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>   

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