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Ublas : |
Subject: Re: [ublas] Getting bit by ormqr.hpp
From: Karl Meerbergen (Karl.Meerbergen_at_[hidden])
Date: 2008-10-16 09:36:45
Correction done.
Karl Meerbergen wrote:
> You are right of course. This should be corrected.
>
> Thanks for spotting this
>
> Karl
>
>
>
> Jeremy Conlin wrote:
>
>> I have been using ormqr.hpp and recently got an error message saying:
>>
>> Parameter 2 to routine ZUNMQR was incorrect
>>
>> This parameter indicates whether a conjugate transpose is to be taken
>> when applying a matrix Q. The valid options for the complex version
>> are 'N' or 'C' (standing for No transpose or Conjugate transpose
>> respectively) while for the single or double version, [DS]ORMQR the
>> valid options are 'N' or 'T' (for No transpose or Transpose
>> respectively). Now the reason I had a problem was because I passed
>> 'T' to the complex version.
>>
>> In ormqr.hpp there is an assert statment to ensure only valid options
>> are passed to ormqr generally:
>>
>> assert ( trans=='N' || trans=='C' || trans=='T' );
>>
>> This obviously didn't catch my problem. It is easy to move this
>> assertion into the more specific functions of ormqr that just call the
>> LAPACK versions. This way you would have one of the two statements
>> below and could avoid the error I got this morning.
>>
>> assert ( trans=='N' || trans=='T'); // For single or double
>> precision
>> assert ( trans=='N' || trans=='C'); // For complex numbers
>>
>> I can make this change and submit a patch, but I wanted to get others'
>> opinions. It seems like the specific functions "want" to remain clean
>> and only make the call to LAPACK and nothing else. That is why I
>> hesitate to put the assert in them.
>>
>> What do you think is the best thing to do? I hope my explanation was
>> clear enough.
>>
>> Thanks,
>> Jeremy Conlin
>> ------------------------------------------------------------------------
>>
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>>
>
>
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