

   SSuumm ooff VVeeccttoorr EElleemmeennttss

        sum(..., na.rm=FALSE)

   DDeessccrriippttiioonn::

        `sum' returns the sum of all the values present in its
        arguments.  If `na.rm' is `FALSE' an `NA' value in any
        of the arguments will cause a value of `NA' to be
        returned, otherwise `NA' values are ignored.

