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Topic: Sparse integer LU decomposition
Replies: 6   Last Post: Dec 15, 2011 7:17 AM

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Pascal Schulthess

Posts: 5
Registered: 12/8/11
Re: Sparse integer LU decomposition
Posted: Dec 8, 2011 11:57 AM
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"Steven_Lord" <slord@mathworks.com> wrote in message <jbqp41$6n1$1@newscl01ah.mathworks.com>...
>
>
> "Pascal Schulthess" <pascal.schulthess@biologie.hu-berlin.de> wrote in
> message news:jbqof0$4bk$1@newscl01ah.mathworks.com...

> > Hi everyone,
> >
> > I was wondering if there is the possibility to perform sparse integer LU
> > decomposition preferably with full pivoting?
> >
> > I've tried to convert to intX and invoke lu(), but an error message is
> > displayed. I would really appreciate any help or hints concerning this.

>
> You can't have sparse integer type matrices in MATLAB.
>
> Even if you could, LU is not defined for integer types in MATLAB (the
> elements of the factors would likely be noninteger values.)
>
> What would you use this functionality to do if it were available? Perhaps
> there's an alternate way to achieve your goal using functionality that is
> available in MATLAB.
>
> --
> Steve Lord
> slord@mathworks.com
> To contact Technical Support use the Contact Us link on
> http://www.mathworks.com


Ok, let me be a little more precise:

Not, I have a large sparse matrix and perform lu decomposition. Ideally, I'd like to convert this sparse matrix to integer and then perform lu. And if I would have three wishes, the resulting matrices would also be sparse and integer :)

But, ok, from you're answers I'm getting that this will not be possible. Perhaps I gotta look into UMFPACK be T. Davis or just ask him if he knows something :)



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