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Index Page rotmat_c

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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

       rotmat_c ( Rotate a matrix )

       void rotmat_c ( ConstSpiceDouble   m1[3][3],
                       SpiceDouble        angle,
                       SpiceInt           iaxis,
                       SpiceDouble        mout[3][3] )

#### Abstract

       Apply a rotation of `angle' radians about axis `iaxis' to a matrix.
       This rotation is thought of as rotating the coordinate system.

#### Required_Reading

       None.

#### Keywords

       MATRIX
       ROTATION

#### Brief_I/O

       VARIABLE  I/O  DESCRIPTION
       --------  ---  --------------------------------------------------
       m1        I     Matrix to be rotated.
       angle     I     Angle of rotation (radians).
       iaxis     I     Axis of rotation (X=1, Y=2, Z=3).
       mout      O     Resulting rotated matrix.

#### Detailed_Input

       m1          is a matrix to which a rotation is to be applied.
                   In matrix algebra, the components of the matrix are
                   relative to one particular coordinate system. Applying
                   rotmat_c changes the components of m1 so that they are
                   relative to a rotated coordinate system.

       angle       is the angle in radians through which the original
                   coordinate system is to be rotated.

       iaxis       is an index for the axis of the original coordinate system
                   about which the rotation by angle is to be performed.
                   iaxis = 1,2 or 3 designates the x-, y- or z-axis,
                   respectively.

#### Detailed_Output

       mout        is the matrix resulting from the application of the
                   specified rotation to the input matrix m1. If

                      [angle]
                            iaxis

                   denotes the rotation matrix by angle radians about iaxis,
                   (see the Rotations Required Reading document) then mout is
                   given by the following matrix equation:

                      mout = [angle]      * m1
                                    iaxis

                   mout can overwrite m1.

#### Parameters

       None.

#### Exceptions

       Error free.

       1)  If the axis index is not in the range 1 to 3, it will be
           treated the same as that integer 1, 2, or 3 that is congruent
           to it mod 3.

#### Files

       None.

#### Particulars

       None.

#### Examples

       Suppose that to rotate the a set of inertial axes to body fixed
       axes, one must first roll the coordinate axes about the x-axis by
       angle r to get x', y', z'. From this one must pitch about the
       y' axis by angle o to get x'', y'', z''.  And finally yaw the
       x'', y'', z'' about the z'' axis by angle y to obtain the
       transformation to bodyfixed coordinates. If id is the identity
       matrix, then the following code fragment generates the
       transformation from inertial to body fixed.

          rotmat_c ( id, r, 1, m1   );
          rotmat_c ( m1, p, 2, m2   );
          rotmat_c ( m2, y, 3, tibf );

#### Restrictions

       None.

#### Literature_References

       None.

#### Author_and_Institution

       N.J. Bachman        (JPL)
       J. Diaz del Rio     (ODC Space)
       W.M. Owen           (JPL)
       W.L. Taber          (JPL)

#### Version

       -CSPICE Version 1.1.1, 13-AUG-2021 (JDR)

           Edited the header to comply with NAIF standard.

       -CSPICE Version 1.1.0, 22-OCT-1998 (NJB)

           Made input matrix const.

       -CSPICE Version 1.0.0, 08-FEB-1998 (NJB) (WMO) (WLT)

           Based on SPICELIB Version 1.0.1, 10-MAR-1992 (WLT)

#### Index_Entries

       rotate a matrix

#### Link to routine rotmat_c source file rotmat_c.c

    Fri Dec 31 18:41:11 2021