cholinv/spcholinv return incorrect results

Gabriele Pannocchia g.pannocchia at ing.unipi.it
Fri Dec 12 12:08:25 CST 2008


Hi,

the following code shows for me a bug in cholinv when the argument is a
sparse matrix.

A = [2,0.2;0.2,1];
issymmetric(A)
min(eig(A))
Ainv = inv(A);
Ainv1 = cholinv(A);
Ainv2 = inv(sparse(A));
Ainv3 = cholinv(sparse(A));
Ainv4 = spcholinv(sparse(A));
err1 = norm(Ainv-Ainv1)
err2 = norm(Ainv-Ainv2)
err3 = norm(Ainv-Ainv3)
err4 = norm(Ainv-Ainv4)

I am using:

----------------------------------------------------------------------
GNU Octave Version 3.0.1
GNU Octave License: GNU General Public License
Operating System: Linux 2.6.24-1-686 #1 SMP Thu May 8 02:16:39 UTC 2008
i686
----------------------------------------------------------------------

Can anyone reproduce this?

Thanks,
	Gabriele



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