[SciPy-user] RREF - upper triangular

Nils Wagner nwagner at mecha.uni-stuttgart.de
Thu Feb 23 07:07:25 CST 2006


Arnd Baecker wrote:
>Hi Nils,
>
>On Thu, 23 Feb 2006, Nils Wagner wrote:
>
>  
>>arnd.baecker at web.de wrote:
>>    
>>>On Wed, 22 Feb 2006, Alan G Isaac wrote:
>>>
>>>      
>>>>On Wed, 22 Feb 2006, Nils Wagner apparently wrote:
>>>>
>>>>        
>>>>>here is a code. However it doesn't make use of LAPACK. So
>>>>>it might be to slow.
>>>>>
>>>>>          
>>>>This exchange suggests to me that Robert thinks that
>>>>wrapping the LAPACK code is approximately trivial but that
>>>>Nils does not see it that way.  Apologies for any
>>>>misunderstanding.
>>>>
>>>>        
>>>But in this particular case previous exposure to wrapping lapack
>>>functions is granted:
>>>http://aspn.activestate.com/ASPN/Mail/Message/scipy-user/2016895
>>>(for dgehrd)
>>>      
>
>[... snipped my remarks on how to use f2py ...]
>
>  
>>If it is so trivial to add the rank revealing QR decomposition to scipy,
>>I would be glad if the several steps on building a wrapper for DGEQP3
>>could be documented on the Wiki as an exercise.
>>The best way to learn something is to have a well-elaborated example. :-)
>>    
>
>Have you *studied* the material I wrote in the snipped part,
>*including* the texts I referred to?
>
>Also, maybe you remember, that the wrapper *you* posted
>at http://aspn.activestate.com/ASPN/Mail/Message/scipy-user/201689
>and claimed to be *yours* was in fact written by *me* for *you*.
>We had an off-list exchange with over 20 mails on this
>in which I tried to guide you step-by-step
>through the Hessenberg wrapping. In course
>of that I also send you a detailed step-by-step example
>on how to wrap band matrices.
>
>So the exercise you propose (including the addition to the wiki)
>is really left to you.
>I am sure that this list will help you with any concrete questions.
>
>I better stop now, before I write things which I might regret later ...
>
>Arnd
>
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>  


Hi Arnd,

It was not my intention to claim that I have build the wrapper. Sorry
for that matter.
Afaik Pearu finally integrated hessenberg into scipy.

Nils



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