VMS Help RTL Routines, MTH$, BLAS1$VxNRM2  *Conan The Librarian (sorry for the slow response - running on an old VAX)

    The Obtain the Euclidean Norm of a Vector routine obtains the
    Euclidean norm of an n-element vector x, expressed as follows:

          ___________________________________
         / x[1]**2 + x[2]**2 + ... + x[n]**2
       \/

    Format

      BLAS1$VSNRM2  n ,x ,incx

      BLAS1$VDNRM2  n ,x ,incx

      BLAS1$VGNRM2  n ,x ,incx

      BLAS1$VSCNRM2  n ,x ,incx

      BLAS1$VDZNRM2  n ,x ,incx

      BLAS1$VGWNRM2  n ,x ,incx

      Use BLAS1$VSNRM2 for single-precision real operations.
      Use BLAS1$VDNRM2 for double-precision real (D-floating)
      operations.
      Use BLAS1$VGNRM2 for double-precision real (G-floating)
      operations.

      Use BLAS1$VSCNRM2 for single-precision complex operations.
      Use BLAS1$VDZNRM2 for double-precision complex (D-floating)
      operations.
      Use BLAS1$VGWNRM2 for double-precision complex (G-floating)
      operations.

1 - Returns

    OpenVMS usage:floating_point
    type:         F_floating, D_floating, or G_floating real
    access:       write only
    mechanism:    by value

    The function value, called e_norm, is the Euclidean norm of
    the vector x. The data type of the function value is a real
    number; for the BLAS1$VSCNRM2, BLAS1$VDZNRM2, and BLAS1$VGWNRM2
    routines, the data type of the function value is the real data
    type corresponding to the complex argument data type.

2 - Arguments

 n

    OpenVMS usage:longword_signed
    type:         longword integer (signed)
    access:       read only
    mechanism:    by reference

    Number of elements in vector x to be processed. The n argument is
    the address of a signed longword integer containing the number of
    elements.

 x

    OpenVMS usage:floating_point or complex_number
    type:         F_floating, D_floating, G_floating real or
                  F_floating, D_floating, G_floating complex
    access:       read only
    mechanism:    by reference, array reference

    Array containing the elements to be accessed. All elements of
    array x are accessed only if the increment argument of x, called
    incx, is 1. The x argument is the address of a floating-point or
    floating-point complex number that is this array. This argument
    is an array of length at least:

    1+(n-1)*|incx|

    where:

    n   =  number of vector elements specified in n
    incx=  increment argument for the array x specified in incx

    Specify the data type as follows:

    Routine            Data Type for x

    BLAS1$VSNRM2       F-floating real
    BLAS1$VDNRM2       D-floating real
    BLAS1$VGNRM2       G-floating real
    BLAS1$VSCNRM2      F-floating complex
    BLAS1$VDZNRM2      D-floating complex
    BLAS1$VGWNRM2      G-floating complex

    If n is less than or equal to 0, then e_norm is 0.0.

 incx

    OpenVMS usage:longword_signed
    type:         longword integer (signed)
    access:       read only
    mechanism:    by reference

    Increment argument for the array x. The incx argument is the
    address of a signed longword integer containing the increment
    argument. If incx is greater than or equal to 0, then x is
    referenced forward in array x; that is, x[i] is referenced in:

    x(1+(i-1)*incx)

    where:

    x   =  array specified in x
    i   =  element of the vector x
    incx=  increment argument for the array x specified in incx

    If you specify a negative value for incx, it is interpreted as
    the absolute value of incx.