[petsc-users] Large matrixes on single machine

[Satish Balay]

On Thu, 28 Apr 2011, Jed Brown wrote:

> On Thu, Apr 28, 2011 at 16:02, Bartłomiej W <bartlomiej.wach at yahoo.pl>wrote:
> 
> > Hello,
> >
> > I was trying to allocate a sparse AIJ matrix of over 800 entries
> >
> > MatSeqAIJSetPreallocation(L,PETSC_NULL,nnz);
> >
> > (with proper nonzeros vector)
> > results in an
> > Maximum memory PetscMalloc()ed 315699888 OS cannot compute size of entire
> > process
> > (in ubuntu)
> 
> 
> What was in the nnz array? If you don't expect the problem to exceed the
> addressable memory, then the array is probably corrupt. If you really mean
> to be solving a very large problem, you will have to get a 64-bit machine
> and configure --with-64-bit-indices, or run in parallel.

What was the complete error message?

The above says '315MB in use'. So was the code trying to allocate 3GB
- when it failed?

Also How many total non-zeros in the matrix?

Satish