io_stopwatch_start Subroutine

  subroutine io_stopwatch_start(tag, timers)
    !=====================================
    !! Stopwatch to time parts of the code
    !=====================================

    use w90_types, only: timer_list_type, nmax

    implicit none

    ! arguments
    type(timer_list_type), intent(inout) :: timers

    character(len=*), intent(in) :: tag
    !! Which stopwatch to act upon
    !integer, intent(in)  :: mode
    !! Action  1=start 2=stop

    ! local variables
    integer :: i
    real(kind=dp) :: t

    call cpu_time(t)

    do i = 1, timers%nnames
      if (timers%clocks(i)%label .eq. tag) then
        timers%clocks(i)%ptime = t
        timers%clocks(i)%ncalls = timers%clocks(i)%ncalls + 1
        return
      end if
    end do

    if (.not. timers%overflow) then
      if (timers%nnames == nmax) then
        timers%overflow = .true.
      else
        timers%nnames = timers%nnames + 1

        timers%clocks(timers%nnames)%label = tag
        timers%clocks(timers%nnames)%ctime = 0.0_dp
        timers%clocks(timers%nnames)%ptime = t
        timers%clocks(timers%nnames)%ncalls = 1
      end if
    end if

    return

  end subroutine io_stopwatch_start