anchor.diff:          ! To avoid any issues, we explicitly set them to the same number
   
           !DEBUG
  -        !call md%check_for_overflow('start')
  +        !call check_for_overflow(md, 'start')
   
           ! Evolve every domain, sending the data to communicate straight after
           ! the evolve
  
positive.code:             d2 = size(md%domains)
          end if
  
          throw_error = .FALSE.
          do j = d1, d2
              do i1 = STG, ELV
                  do i2 = 1, md%domains(j)%nx(2)
                      do i3 = 1, md%domains(j)%nx(1)
                          if((md%domains(j)%U(i3, i2, i1) >  bignum) .or. &
                             (md%domains(j)%U(i3, i2, i1) < -bignum) .or. &
                             (md%domains(j)%U(i3, i2, i1) /= md%domains(j)%U(i3, i2, i1))) then
                             throw_error = .TRUE.
                             write(log_output_unit,*) flag
                             write(log_output_unit,*) 'md%domains(', j,')%U(', i3, i2, i1, ')'
                             write(log_output_unit,*) md%domains(j)%U(i3, i2, i1)
                             write(log_output_unit,*) 'x: ', md%domains(j)%x(i3), '; y: ', md%domains(j)%y(i2)
                             write(log_output_unit,*) 'time: ', md%domains(j)%time
                             write(log_output_unit,*) 'stg:elv, ', md%domains(j)%U(i3, i2, STG:ELV)
                             if(md%domains(j)%nesting%my_index > 0) then
                                 write(log_output_unit,*) 'priority domain index'
                                 write(log_output_unit,*) md%domains(j)%nesting%priority_domain_index(i3, i2)
                                 write(log_output_unit,*) 'priority domain image'
                                 write(log_output_unit,*) md%domains(j)%nesting%priority_domain_image(i3, i2)
                             end if
                          end if
                      end do
                  end do
              end do
          end do
  
          if(throw_error) then
              flush(log_output_unit)
              call generic_stop
          end if
  
      end subroutine
  
  
      ! Communicate max-stage array in halo regions.
      !
  
negative.code:             TIMER_STOP('nesting_flux_correction')
  
              !DEBUG
              !call check_for_overflow(md, 'step-after-flux_correct')
          end if
  
      end subroutine
  