flow_global_max_owned Function

public function flow_global_max_owned(flow, a) result(global_max)

Uses

Computes the global maximum magnitude of a field over owned cells.

Arguments

Type IntentOptional Attributes Name
type(flow_mpi_t), intent(in) :: flow
real(kind=rk), intent(in) :: a(:)

Return Value real(kind=rk)


Source Code

   function flow_global_max_owned(flow, a) result(global_max)
      use mod_profiling, only : profiler_start, profiler_stop
      type(flow_mpi_t), intent(in) :: flow
      real(rk), intent(in) :: a(:)
      real(rk) :: global_max, local_max
      integer :: c, ierr

      local_max = 0.0_rk
      do c = flow%first_cell, flow%last_cell
         local_max = max(local_max, abs(a(c)))
      end do

      if (flow%nprocs == 1) then
         global_max = local_max
         return
      end if

      call profiler_start('MPI_Communication')
      call MPI_Allreduce(local_max, global_max, 1, MPI_DOUBLE_PRECISION, MPI_MAX, flow%comm, ierr)
      call check_mpi(ierr, 'MPI_Allreduce flow max')
      call profiler_stop('MPI_Communication')
   end function flow_global_max_owned