CSPICE_VDISTG returns the double precision value of the distance between
two double precision N-vectors.
For important details concerning this module's function, please refer to
the CSPICE routine vdistg_c.
vec2 two double precision N-vectors, the distance between
which is desired.
dist = cspice_vdistg( vec1, vec2 )
dist double precision scalar distance between 'vec1' and 'vec2'.
This is defined as
|| v1 - v2 ||,
where || x || indicates the Euclidean norm of the vector x.
Any numerical results shown for this example may differ between
platforms as the results depend on the SPICE kernels used as input
and the machine specific arithmetic implementation.
vec1 = [ 12.3d, -4.32d, 76.d, 1.87d ]
vec2 = [ 23.0423d, -11.99d, -0.10d, -99.1d ]
print, cspice_vdistg( vec1, vec2)
Native IDL code to calculate the same scalar result:
norm( vec1 - vec2 )
The IDL function accepts an arbitrary size N-vectors.
The Euclidean norm of an n-dimensional vector
(x , x , ... , x )
1 2 n
is defined as
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
( a, a, a ) and ( b, b, b ),
then the distance between A and B is the norm of the difference
A - B, which has components
( a - b, a - b, a - b ).
A related routine is cspice_vdist, which computes the distance between
-Icy Version 1.0.1, 13-JUN-2011, EDW (JPL)
Edits to comply with NAIF standard for Icy headers.
-Icy Version 1.0.0, 16-JUN-2003, EDW (JPL)
distance between n-dimensional vectors