noob: umf_lufact not enough memory

[Martin S]

Hi everyone,
I'm doing a little finite differences implementation of the 3D Poisson-
Boltzmann equation, and I end up with the task of finding the
eigenvector of that huge sparse matrix. The best thing to do seems to
use the the umf_lufact and umf_lusolve functions, however this is
strongly limited by the memory available to SciLab (I'm using a
computer with 4GB of RAM), even after setting the stacksize to 'max'.
In fact, I get the "not enough memory"-error from ump_lufact.
My question is, whether increasing the size of the swap partition on a
linux system would give me the possibility to push the limits of the
stacksize, thereby enabling me to increase the resolution of my
simulations.
Thanks and cheers

[bruno]

Hi,

I think you should not put the stacksize to the max because the
memory of lu factors
are outside the stack (this is for this reason that you should free
the memory with
umf_ludel and not with clear). Note also that with 3D computation the
lu factors needs
many places (fill in in more severe than in 2D, moreover the
reordering algorithm
used (amd) is not the best for 3D).

hth
Bruno