tril/triu not preserving sparseness

[Martijn van Oosterhout]

Hi,

I'm working with matrices 6380x6380 and building them sparse. However,
if I do tril/triu on them it tries to build a full matrix and
immediately runs out of memory..
I'm on Octave 2.9.9 and the code for these functions contains the line:

    retval = resize (resize (x, 0), nr, nc);

This returns a full matrix even if x is sparse. If I comment that line
out it runs fine, but the final matrix is not of the right dimensions
(depending on the value of k). So at the end of the function I put the
line:

  retval = resize (retval, nr, nc);

And now octave segfaults. I just need a version of tril/triu that
works with sparse matrices, anyone have any tips?

Have a nice day,

-- 
Martijn van Oosterhout <address@hidden> http://svana.org/kleptog/