CODEWITHSUNDEEP
mpi
Gilgamesz
Gilgamesz

Reputation: 5073

MPI. Maximum number of communicators and processes

I would like to ask two questions:

What is maximal number of communicators in MPI? What is maximal number of processes in MPI?

Upvotes: 2

Views: 1642

Answers (1)

Gilles Gouaillardet
Gilles Gouaillardet

Reputation: 8395

This is very likely implementation dependent. the standard states a rank is an int, and in Fortran (before Fortran 2008 bindings) a communicator is a Fortran integer (which might not have the same size than a C integer) bottom line, i think there is a hard limit of 2 billion MPI tasks in MPI_COMM_WORLD, and there is likely a similar hard limit of 2 billion communicators. once again, a given implementation might have lower limits.

Upvotes: 3

Related Questions