Procedure

   void ident_c ( SpiceDouble    matrix[3][3] ) 

Abstract

 
  This routine returns the 3x3 identity matrix. 
 

Required_Reading

 
   None. 
 

Keywords

 
   MATRIX 
 

Brief_I/O

 
   VARIABLE  I/O  DESCRIPTION 
   --------  ---  -------------------------------------------------- 
   matrix     O   is the 3x3 identity matrix. 
 

Detailed_Input

 
   None. 
 

Detailed_Output

 
   matrix     is the 3x3 Identity matrix.  That is MATRIX is 
              the following 
                _                 _ 
               |  1.0   0.0   0.0  |
               |  0.0   1.0   0.0  | 
               |  0.0   0.0   1.0  | 
                -                  - 

Parameters

 
   None. 
 

Exceptions

 
   Error free. 
 

Files

 
   None. 
 

Particulars

 
   This is a utility routine for obtaining the 3x3 identity matrix 
   so that you may avoid having to write the loop or assignments 
   needed to get the matrix. 
 

Examples

 
   Suppose that you need to construct the matrix sum 
 
      ident + omega 
 
   where omega is some matrix you have already computed. 
 
   The code fragment below shows how you could accomplish this 
   with this routine. 
 
      First get the Identity matrix 
      
      #include "SpiceUsr.h"
            .
            .
            .
         
      SpiceDouble             ident[3][3];
 
      ident_c ( ident ); 
      vaddg_c ( ident, omega, 9, sum ); 
 
 

Restrictions

 
   None. 
 

Literature_References

 
   None. 
 

Author_and_Institution

 
   N.J. Bachman    (JPL)
   W.L. Taber      (JPL) 
 

Version

 
   -CSPICE Version 1.0.0, 1-JUN-1999 (NJB) (WLT)

Index_Entries

 
   Get the 3x3 identity matrix 
 

Link to routine ident_c source file ident_c.c