Index Page
vdist_c
A  B  C  D  E  F  G  H  I  J  K  L  M  N  O  P  Q  R  S  T  U  V  W  X 

Procedure
Abstract
Required_Reading
Keywords
Brief_I/O
Detailed_Input
Detailed_Output
Parameters
Exceptions
Files
Particulars
Examples
Restrictions
Literature_References
Author_and_Institution
Version
Index_Entries

Procedure

   SpiceDouble vdist_c ( ConstSpiceDouble v1[3],
                         ConstSpiceDouble v2[3] )

Abstract

   Return the distance between two three-dimensional vectors.

Required_Reading

   None.

Keywords

   VECTOR


Brief_I/O

   Variable  I/O  Description
   --------  ---  --------------------------------------------------

   v1,
   v2         I   Two 3-vectors.

   The function returns the distance between v1 and v2.

Detailed_Input

   v1,
   v2         are two vectors in three-dimensional space, the
              distance between which is desired.

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.

Parameters

   None.

Exceptions

   Error free.

Files

   None.

Particulars

   This function is simply shorthand for the code

      vsub_c ( v1, v2, diff );

      dist = vnorm_c ( diff );

   Using this function saves you the annoyance of declaring local
   storage for the difference vector diff.


   The Euclidean norm of a three-dimensional vector (x, y, z) is
   defined as

                                   1/2
           2        2        2
      (   x    +   y    +   z    ).


   This number is the distance of the point (x, y, z) from the
   origin.  If 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 vdistg_, which computes the distance between
   two vectors of general dimension.

Examples

   1)  If v1 is

          ( 2.0,  3.0,  0. )

       and v2 is

          ( 5.0,  7.0,  12. ),

       vdist_c (v1, v2) will be 13..


   2)  If VGR2 and NEP are states of the Voyager 2 spacecraft and
       Neptune with respect to some common center at a given time
       ET, then

          vdist_c ( VGR2, NEP )

       yields the distance between the spacecraft and Neptune at time
       ET.

Restrictions

   None.

Literature_References

   None.

Author_and_Institution

   N.J. Bachman   (JPL)

Version

   -CSPICE Version 1.2.0, 22-OCT-1998 (NJB)

      Made input vectors const.  Removed #include of SpiceZfc.h.

   -CSPICE Version 1.1.0, 06-MAR-1998   (EDW)

      Removed non printing character.

   -CSPICE Version 1.0.0, 08-FEB-1998   (EDW)

Index_Entries

   distance between 3-dimensional vectors
Wed Apr  5 17:54:46 2017