Current implementations have several subroutines for performing reduction operations:
C maximum (integer)
subroutine mesh_merge_int_max(isize, int_in, int_out)
integer int_in(isize), int_out(isize)
C maximum absolute value (real)
subroutine mesh_merge_real_maxabs(isize, real_in, real_out)
real real_in(isize), real_out(isize)
C sum (real)
subroutine mesh_merge_real_sum(isize, real_in, real_out)
real real_in(isize), real_out(isize)
C synchronize only
subroutine mesh_synch
Additional subroutines may be provided in future implementations, depending on feedback from users. Users are also welcome to write their own reduction subroutines by scavenging code from the provided routines. (E.g., a subroutine for computing a global minimum is almost identical to a subroutine for computing a global maximum.)