| Re: [eigen] Computing left nullspace of A when rows > cols |
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- To: eigen@xxxxxxxxxxxxxxxxxxx
- Subject: Re: [eigen] Computing left nullspace of A when rows > cols
- From: Benoit Jacob <jacob.benoit.1@xxxxxxxxx>
- Date: Fri, 30 Jan 2009 18:54:24 +0100
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2009/1/30 Keir Mierle <mierle@xxxxxxxxx>:
> Just to second a request for this: Many applications use the SVD to
> form a basis for the nullspace of A, where A is 'wide'; this is the
> same here as the left nullspace of a 'tall' matrix.
>
> In libmv, I solve this problem by padding wide matrices with zeros on
> the bottom until they are square, then pass to the SVD. Suboptimal,
> but it works well enough for now.
>
> I will see about the SVD later this week.
Just to tell you where I am: I'm looking very closely at Householder
and Givens operations right now but for the math project i'm doing,
not for Eigen. So while i'm not doing the SVD now I'm doing stuff that
prepares me well to do it ASAP.
Just so you don't think i've abandoned this project!
Cheers
Benoit