Re: Novice question on A \ b

[John B. Thoo]

On Mar 10, 2005, at 5:05 PM, Geordie McBain wrote:

> > octave:18> A = [ [1, 1, 2, 3]' [0, 0, 4, 4]']; b = [3, 0, -1, 0]'; A 
> > \ b
> > ans =
> >
> >    1.40000
> >   -1.00000
> >
> >
> > I think this is the minimum norm solution, but Octave did not issue a
> > warning.  What is wrong with my thinking?
>
> I think Octave only warns when a square matrix is (numerically)
> singular.  Since no nonsquare matrices are nonsingular, it could
> reasonably be argued that the warning would be redundant.

Brilliant.  That makes sense to me.  Thanks. :-)

---John.



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