ILP64 support

[AidanGG]

Hello, I was wondering if CTF supported the 64-bit integer interface to MKL BLAS, LAPACK and ScaLAPACK for arrays with more than 2^31 - 1 elements. For extremely large tensors, this is even more important because a global ScaLAPACK descriptor using 32-bit ints limits the size of the global matrix, not just the local ones.

From what I can tell from the source, the wrappers make use of hard-coded int. Would it be possible to add a build directive to enable the ILP64 interface when building with MKL?

[solomonik]

Thanks for the suggestion, it would be possible to add this support, but will require a bit of work. We will try to add this soon.

[AidanGG]

I believe ILP64 support has recently been merged into Reference ScaLAPACK (Reference-ScaLAPACK/scalapack#19) so in principle CTF would be able to use 64-bit ints for ScaLAPACK regardless of implementation (MKL or reference).