singular matrix

[Matthew Knepley]

On Thu, Apr 16, 2009 at 10:22 AM, Yixun Liu <enjoywm at cs.wm.edu> wrote:

> Hi,
> For Ax=b, A is mxn, m>n. I use CG to resolve it and find the solution
> makes no sense.  I guess rank(A) < min(m,n). How to resolve this
> singular system? Use SVD?


CG is a method for SPD matrices. This matrix is not symmetric. You appear
to be solving a least squares problem. I would read about these a little.
Ake
Bjorck has a pretty good book.

  Matt


>
> Best,
>
> Yixun
>
-- 
What most experimenters take for granted before they begin their experiments
is infinitely more interesting than any results to which their experiments
lead.
-- Norbert Wiener
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