Re: [Chageset]: Add the spaugment function

[Ben Abbott]

On Apr 2, 2008, at 1:12 PM, David Bateman wrote:
> Another easy function to implement. The help string and the example  
> took
> longer to write :-)
>
> D.

David, I'm getting a failure with this one.

Is there reason for concern?

In event it is important, I built with SuiteSparse 3.1.0.

octave:5> test spaugment
  ***** test
 m = 11; n = 10; mn = max(m ,n);
 a = spdiags ([ones(mn,1), 10*ones(mn,1), -ones(mn,1)],[-1,0,1], m, n);
 x0 = a \ ones (m,1);
 s = spaugment (a);
 [L, U, P, Q] = lu (s);
 x1 = Q * (U \ (L \ (P  * [ones(m,1); zeros(n,1)])));
 x1 = x1(end - n + 1 : end);
 assert (x1, x0, 1e-10)
!!!!! test failed
error: assert (x1,x0,1e-10) expected
   0.109902
   0.099020
   0.100097
   0.099990
   0.100001
   0.100000
   0.099990
   0.099990
   0.099020
   0.099020
but got
   0.109902
   0.099020
   0.100097
   0.099990
   0.100001
   0.100000
   0.099990
   0.099990
   0.099020
   0.099020
maximum absolute error 1.655e-07 exceeds tolerance 1e-10

Ben