Procedure

   void vupack_c ( ConstSpiceDouble     v[3],
                   SpiceDouble        * x,
                   SpiceDouble        * y,
                   SpiceDouble        * z     ) 

Abstract

 
   Unpack three scalar components from a vector. 
 

Required_Reading

 
   None. 
 

Keywords

 
   VECTOR 
 

Brief_I/O

 
   VARIABLE  I/O  DESCRIPTION 
   --------  ---  -------------------------------------------------- 
   v          I   3-vector.
   x, 
   y, 
   z          O   Scalar components of 3-vector. 

Detailed_Input

 
   v           is a double precision 3-vector.
 

Detailed_Output

 
   x, 
   y, 
   z           are the scalar components of the 3-vector v.  On output,
               the following equalities hold:
 
                  x = v[0]
                  y = v[1]
                  z = v[2] 

Parameters

 
   None. 
 

Exceptions

 
   Error free. 
 

Files

 
   None. 
 

Particulars

 
   Basically, this is just shorthand notation for the common 
   sequence 

      x = v[0];
      y = v[1];
      z = v[2] ;

   The routine is useful largely for two reasons. First, it 
   reduces the chance that the programmer will make a "cut and 
   paste" mistake, like 

      x = v[0];
      y = v[0];
      z = v[0]; 

   Second, it makes conversions between equivalent units simpler, 
   and clearer. For instance, the sequence 

      x = v[0] * rpd_c(); 
      y = v[1] * rpd_c();
      z = v[2] * rpd_c();

   can be replaced by the (nearly) equivalent sequence 

      vscl_c   ( rpd_c(),  v,   v  ); 
      vupack_c ( v,  &x,  &y,  &z  ); 

Examples

 
   See: Detailed_Description. 
 

Restrictions

 
   None. 
 

Literature_References

 
   None. 
 

Author_and_Institution

   
   N.J. Bachman    (JPL)
   I.M. Underwood  (JPL) 
 

Version

 
   -CSPICE Version 1.0.0, 07-NOV-2006 (NJB)

      Corrected header errors that claimed this routine
      performs the function of vpack_c.

   -CSPICE Version 1.0.0, 28-JUN-1999 (IMU) (NJB)

Index_Entries

 
   unpack three scalar components from a vector 
 

Link to routine vupack_c source file vupack_c.c