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

  INTEGER*4 ISAMAX (n, x, incx)
  INTEGER*4 IDAMAX (n, x, incx)
  INTEGER*4 ICAMAX (n, x, incx)
  INTEGER*4 IZAMAX (n, x, incx)

  Functions that return the index of the first selected element of
  the array argument which has the maximum absolute value.

  These functions are part of the BLAS1 Basic Set, and are only
  available on VAX processors.

  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 ISAMAX,
    REAL*8 for IDAMAX, COMPLEX*8 for ICAMAX, COMPLEX*16 for IZAMAX.

    incx

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