Procedure

     VDISTG ( Vector distance, general dimension )

     DOUBLE PRECISION FUNCTION VDISTG ( V1, V2, NDIM )

Abstract

     Return the distance between two vectors of arbitrary dimension.

Required_Reading

     None.

Keywords

     VECTOR

Declarations

     IMPLICIT NONE

     DOUBLE PRECISION      V1   ( * )
     DOUBLE PRECISION      V2   ( * )
     INTEGER               NDIM

Brief_I/O

     VARIABLE  I/O  DESCRIPTION
     --------  ---  --------------------------------------------------
     V1,
     V2         I   Two vectors of arbitrary dimension.
     NDIM       I   The common dimension of V1 and V2

     The function returns the distance between V1 and V2.

Detailed_Input

     V1,
     V2       are two vectors of arbitrary dimension, the
              distance between which is desired.

     NDIM     is the common dimension of V1 and V2. NDIM must be
              non-negative and must not exceed the minimum of the
              declared sizes of the actual arguments corresponding
              to V1 and V2.

Detailed_Output

     The function returns the distance between V1 and V2. This is
     defined as

        ||  V1 - V2  ||,

     where || x || indicates the Euclidean norm of the vector x.

     If NDIM is less than 1, the function value is set to 0.D0.

Parameters

     None.

Exceptions

     Error free.

Files

     None.

Particulars

     The Euclidean norm of an n-dimensional vector

        (x ,  x , ... , x )
          1    2         n

     is defined as

                                                1/2
              2        2                  2
        (   x    +   x    +  . . .  +   x     ).
             1        2                  n

     This number is the distance of the point (x, y, z) from the
     origin. If n = 3, and A and B are two vectors whose components
     are

        ( A(1), A(2), A(3) )    and    ( B(1), B(2), B(3) ),

     then the distance between A and B is the norm of the difference
     A - B, which has components

        (  A(1) - B(1),  A(2) - B(2),  A(3) - B(3)  ).

     A related routine is VDIST, which computes the distance between
     two 3-vectors.

Examples

     1)  If V1 is

            ( 2.0D0,  3.0D0 )

         and V2 is

            ( 5.0D0,  7.0D0 ),

         and NDIM is 2, then

            VDISTG (V1, V2, NDIM )

         will be 5.D0.

Restrictions

     None.

Literature_References

     None.

Author_and_Institution

     N.J. Bachman       (JPL)
     J. Diaz del Rio    (ODC Space)
     W.L. Taber         (JPL)

Version

    SPICELIB Version 1.1.0, 25-MAY-2021 (JDR)

        Added IMPLICIT NONE statement.

        Edited the header to comply with NAIF standard.

    SPICELIB Version 1.0.1, 10-MAR-1992 (WLT)

        Comment section for permuted index source lines was added
        following the header.

    SPICELIB Version 1.0.0, 17-JUL-1990 (NJB)