large sparse matrix

[Carlo de Falco]

Hi,

I am using the OSX binary version of octave 3.2.2.
I am having trouble solving a linear system with a large but quite
sparse coefficient matrix, the problem can be reproduced by:

octave-3.2.2:1> mat = sprandn (20e3,20e3,6e-3);
octave-3.2.2:2> rhs = ones (20e3, 1);
octave-3.2.2:3> x = mat\rhs;
octave-3.2.2(56985) malloc: *** mmap(size=2147483648) failed (error code=12)
*** error: can't allocate region
*** set a breakpoint in malloc_error_break to debug

<and many more simila errors>

although large, this system seems much smaller than the amount of
memory I have on my machine (4Gb), and also smaller than the 32 bit
indexing limits.
Is this a bug or is there some other limits I should consider that I
am forgetting?

c.