CSPICE Routines: IDENT

(Index) | A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

IDENT_C: Return the 3x3 identity matrix

Abstract

  This routine returns the 3x3 identity matrix.

Required_Reading
```
   None. 
```

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. 
```

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. 
```
Exceptions
```
   Error free. 
```
Files
```
   None. 
```

Author_and_Institution

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

Literature_References
```
   None. 
```

Version

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

Index_Entries
```
   Get the 3x3 identity matrix 
```
Link to routine source

(Index) | A B C D E F G H I J K L M N O P Q R S T U V W X Y Z