VMS Help FORTRAN, Statements, Directive Statements, NOVECTOR  *Conan The Librarian (sorry for the slow response - running on an old VAX)

  CDEC$ NOVECTOR

  The CDEC$ NOVECTOR directive tells the compiler not to vectorize
  the DO loop following the directive.  This is useful in cases where
  the vectorized form would not perform as well as the scalar form.
  This directive is only available on VAX processors.

  The NOVECTOR directive must precede the DO statement for each DO
  loop to which you want the directive to apply.  No source code
  lines, other than the following can be placed between the NOVECTOR
  directive statement and the DO statement:  an optional CPAR$
  DO_PARALLEL directive, a CDEC$ INIT_DEP_FWD directive, placeholder
  lines, comment lines, or blank lines.