/sys$common/syshlp/helplib.hlb FORTRAN, Intrinsic Procedures, NWORKERS  *Conan The Librarian (sorry for the slow response - running on an old VAX)

  The intrinsic function NWORKERS requires no arguments and returns
  an INTEGER*4 value that represents the total number of processes
  executing an application.  NWORKERS will be most useful in parallel
  applications for determining the size of the iteration segments to
  be executed by the parallel processes.  For example:
    CPAR$ DO_PARALLEL  (N+NWORKERS( )-1) / NWORKERS( )
          DO I = 1, N
          ...
          ENDDO
  In this example, the size of each iteration segment to be executed
  in the parallel processes would be the total number of iterations
  in the parallel DO loop divided by the number of available
  processes.  (Specifying "(N+NWORKERS( )-1)" guarantees that you can
  never get an illegal segment value of 0.)

  By using NWORKERS as a variable in the calculation to establish
  iteration segment size, the segment size adjusts automatically when
  the application is run on systems with varying numbers of available
  processors.