Global efforts
This is an example of cs_user_extra_operations which computes global efforts
Local variables to be added
integer          ifac
integer          ii
integer          ilelt  , nlelt
double precision xfor(3)
integer, allocatable, dimension(:) :: lstelt
Body
Example: compute global efforts on a subset of faces. If efforts have been calculated correctly:
    xfor(ii) = 0.d0
  enddo
  call 
getfbr(
'2 or 3', nlelt, lstelt)
  
  do ilelt = 1, nlelt
    ifac = lstelt(ilelt)
      xfor(ii) = xfor(ii) + 
forbr(ii, ifac)
    enddo
  enddo
  endif
endif