Name

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  MGH_ROTATE

Purpose

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  This provides a handy shortcut for rotation of vectors on the
  X,Y plane. Given arguments x & 7 representing
  x & y components, respectively, and an angle, the
  procedure rotates the (x,y) vector through the angle using the mathematical
  convention (radians, anti-clockwise) and returns the components of the result.
 
  The arguments can all be scalars or arrays. Incompatible dimensions will
  be picked up during processing.

Calling Sequence

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  mgh_rotate, x, y, angle
  POSITIONAL ARGUMENTS:
  x, y (non-complex scalar or array, input and output)
      X & Y components of the vector, modified on output.
  angle (numeric scalar or array)
      Angle in radians. (A complex value of angle is permitted and
      will produce a change in the vector length.)
###########################################################################
  This software is provided subject to the following conditions:
  1. NIWA makes no representations or warranties regarding the
    accuracy of the software, the use to which the software may
    be put or the results to be obtained from the use of the
    software. Accordingly NIWA accepts no liability for any loss
    or damage (whether direct of indirect) incurred by any person
    through the use of or reliance on the software.
  2. NIWA is to be acknowledged as the original author of the
    software where the software is used or presented in any form.
###########################################################################

Modification History

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  Mark Hadfield, 2011-12:
    Written.