era.ry.md

eraRy

ERFA.ry(theta, r)

Rotate an r-matrix about the y-axis.

Given:

   theta  double          angle (radians)

Given and returned:

   r      double[3][3]    r-matrix, rotated

Notes:

1. Calling this function with positive theta incorporates in the supplied r-matrix r an additional rotation, about the y-axis, anticlockwise as seen looking towards the origin from positive y.

2) The additional rotation can be represented by this matrix:

       (  + cos(theta)     0      - sin(theta)  )
       (                                        )
       (       0           1           0        )
       (                                        )
       (  + sin(theta)     0      + cos(theta)  )

This revision: 2021 May 11

Copyright (C) 2013-2021, NumFOCUS Foundation. Derived, with permission, from the SOFA library.