For a grid with the size of N X N X N values, using the FORTRAN data type of REAL to represent each value, it use of memory can be represented in the following way.

A REAL value contains .

There are .

From http://www.hpc.unm.edu/systems-table

Pequena allows 8 GB RAM/Host Node.

These first two evaluate grids with eight processes per node.

1.

2.

These next two evaluate eight processes on four nodes, or 2 processes per node.

3.

4.

I would expect a grid size of 1000X1000X1000 with 2 processes per node to not have a memory problem, however I experience errors in this situation.