VMS Help FORTRAN, Intrinsic Procedures, xSUM  *Conan The Librarian (sorry for the slow response - running on an old VAX)

  REAL*4      SSUM (n, x, incx)
  REAL*8      DSUM (n, x, incx)
  COMPLEX*8   CSUM (n, x, incx)
  COMPLEX*16  ZSUM (n, x, incx)

  Functions that return the sum of the selected elements of array
  "x".

  These routines are part of the BLAS1 Extended Set, and are
  available only on VAX processors.  The Compaq Extended Math
  Library product may be needed to resolve references to Extended Set
  routines that are not expanded inline by the compiler.

  Arguments

    n

    Integer number of elements in array "x" to be accessed.

    x

    Array containing the elements to be accessed or array reference
    to the first such element.  The data type is REAL*4 for SSUM,
    REAL*8 for DSUM, COMPLEX*8 for CSUM, COMPLEX*16 for ZSUM.

    incx

    Integer index increment used in selecting which elements of array
    "x" are accessed.