VMS Help RTL Routines, MTH$, BLAS1$VIxAMAX, Returns  *Conan The Librarian (sorry for the slow response - running on an old VAX)

    OpenVMS usage:longword_signed
    type:         longword integer (signed)
    access:       write only
    mechanism:    by value

    For the real versions of this routine, the function value is
    the index of the first occurrence of a vector element having the
    maximum absolute value, as follows:

                   |xi | = ma{ |j | for j = 1,2,...,n}
                             {                       }

    |x[i]| = max{|x[j]| for j = 1,2,...,n}

    For the complex versions of this routine, the function value
    is the index of the first occurrence of a vector element having
    the largest sum of the absolute values of the real and imaginary
    parts of the vector elements, as follows:

     |Re(xi )|+|Im(xi )| = ma{ |Re(j )|+|Im(xj)| for j = 1,2,...,n }
                             {                                     }

    |Re(x[i])|  +  |Im(x[i])|   =
    max{|Re(x[j])|+|Im(x[j])|  for j = 1,2,...,n}