vnorm_c

Index Page vnorm_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 vnorm_c ( ConstSpiceDouble v1[3] )
#### Abstract
       Compute the magnitude of a double precision, 3-dimensional vector.
#### Required_Reading
       None.
#### Keywords
       VECTOR
#### Brief_I/O
       VARIABLE  I/O  DESCRIPTION
       --------  ---  --------------------------------------------------
       v1         I   Vector whose magnitude is to be found.

       The function returns the norm of v1.
#### Detailed_Input
       v1             may be any 3-dimensional, double precision vector.
#### Detailed_Output
       The function returns the magnitude of v1 calculated in a numerically
       stable way.
#### Parameters
       None.
#### Exceptions
       Error free.
#### Files
       None.
#### Particulars
       vnorm_c takes care to avoid overflow while computing the norm of the
       input vector v1.  vnorm_c finds the component of v1 whose magnitude
       is the largest.  Calling this magnitude v1max, the norm is computed
       using the formula

           vnorm_c  =  v1max *  ||  (1/v1max) * v1  ||

       where the notation ||x|| indicates the norm of the vector x.
#### Examples
       The following table show the correlation between various input
       vectors v1 and vnorm_c:

       v1                                    vnorm_c
       -----------------------------------------------------------------
       ( 1.e0,    2.e0,   2.e0    )          3.e0
       ( 5.e0,    12.e0,  0.e0    )          13.e0
       ( -5.e-17, 0.0e0,  12.e-17 )          13.e-17
#### Restrictions
       None.
#### Literature_References
       None.
#### Author_and_Institution
       N.J. Bachman       (JPL)
       W.L. Taber         (JPL)
       W.M. Owen          (JPL)
#### Version
       -CSPICE Version 1.0.2, 16-JAN-2008   (EDW)

          Corrected typos in header titles:

          Detailed Input to Detailed_Input
          Detailed Output to Detailed_Output

       -CSPICE Version 1.0.1, 12-NOV-2006 (EDW)

          Added Parameters section header.

       -CSPICE Version 1.0.0, 16-APR-1999 (NJB)
#### Index_Entries
       norm of 3-dimensional vector
#### Link to routine vnorm_c source file vnorm_c.c

    Thu Apr 16 08:59:32 2009