## Example 15 (64-bit version)

This example is a slight modification of Example 15 that illustrates the 64-bit integer support in hypre needed to run problems with more than 2B unknowns.

Specifically, the changes compared to Example 15 are as follows:

1. All integer arguments to HYPRE functions should be declared of type HYPRE_Int.
2. Variables of type HYPRE_Int are 64-bit integers, so they should be printed in the %lld format (not %d).

To enable the 64-bit integer support, you need to build hypre with the --enable-bigint option of the configure script. We recommend comparing this example with Example 15.