Re: Memory exhausted when using \

[Martin Helm]

Am 17.07.2012 13:07, schrieb Mathieu Dubois:
> Hi Martin,
>
> Sorry for the delay (I have a lot of other problems :).
>
> I have installed lsqrSOL and used your snippet (except that I set atol
> = btol = 1e6). It seems to work (but it's rather slow compared to the
> matlab implementation which use \).
>
> I will try to make sure that the results are similar.
>
> Thanks for your help,
> Mathieu

I can - like Jordi also posted - now reproduce the problem, I cannot
look into it tonight.
I noticed that you use a sparse vector for b, and made a quick
interesting test

octave:1> load memory-exhausted
octave:2> tic;X = lsqrSOL(rows(A), columns(A), A, b, 0, 1e-6, 1e-6, 1e8,
1000, 0);toc
Elapsed time is 13.6464 seconds.
octave:3> b = full(b);
octave:4> tic;X = lsqrSOL(rows(A), columns(A), A, b, 0, 1e-6, 1e-6, 1e8,
1000, 0);toc
Elapsed time is 4.46147 seconds.

If I convert b to a full vector the lsqrSOL is 3 times faster! funny

I look tomorrow into the memory exhausted for A\b, that simply should
not happen given the amount of nonzero elements in A and it has a nice
banded structure when I look with spy(A) at it.