code: def ellpoint (mjr, mnr, pa, th):
      
      _ellcheck (mjr, mnr, pa)
      from numpy import cos, sin
  
      ct, st = cos (th), sin (th)
      cp, sp = cos (pa), sin (pa)
      x = mjr * cp * ct - mnr * sp * st
      y = mjr * sp * ct + mnr * cp * st
      return x, y
docs: Compute a point on an ellipse parametrically. Inputs:
  
      * mjr: major axis (sigma not FWHM) of the ellipse
      * mnr: minor axis (sigma not FWHM) of the ellipse
      * pa: position angle (from +x to +y) of the ellipse, radians
      * th: the parameter, 0 <= th < 2pi: the eccentric anomaly
  
      Returns: (x, y)
  
      th may be a vector, in which case x and y will be as well.