On 2013-03-13, Ether Jones <maxima at etherjones.us> wrote:
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>> Try UPM Octave Version 7 by F. Herraiz.
>
> Is there an English version?
Sage (http://www.sagemath.org) does QR factorization with arbitrary
precision.
It also has an interface to Maxima, so doing QR on matrices you get from
Maxima should be trivial.
>
>
>
> ________________________________
> From: Wolfgang Lindner <LindnerW at t-online.de>
> To: Ether Jones <maxima at etherjones.us>
> Sent: Sunday, March 10, 2013 2:59 AM
> Subject: Re: [Maxima] QR factorization & backsubstitution
>
>| I'm familiar with Octave but have been waiting for a stable native binary
> distro for Windows.
>| Is there one you recommend?
>
> Try UPM Octave Version 7 by F. Herraiz.
>
> Wolfgang
>
> ________________________________
> From: Przemek Klosowski <przemek.klosowski at nist.gov>
> To: Ether Jones <maxima at etherjones.us>
> Sent: Friday, March 8, 2013 11:19 AM
> Subject: Re: [Maxima] QR factorization & backsubstitution
>
> On 03/07/2013 08:01 PM, Ether Jones wrote:
>> Does Maxima have QR factorization built in?
>>
>> i.e. A = Q*R
>>
>> where A has more rows than columns, Q is orthogonal, and R is upper
>> triangular?
>>
>> Also, does Maxima have a backsubstitution method, so that
>> the overdetermined linear system Ax~b can be solved using QR
>> factorization by solving Rx=Q'b by backsubstitution?
>
> Since you're asking for a numerical solution, I would recommend using a
> numerics-oriented package such as Octave, which indeed has QR and
> backsubstitution. I am pretty sure that Maxima can get access to the same
> functionality (it's LAPACK after all) but you may need some extra work to
> get to it while it's bread and butter to Octave which is a FOSS Matlab clone
> in case you're not familiar with it.