code: public static INDArray atan2(@NonNull INDArray x, @NonNull INDArray y) {
          return Nd4j.getExecutioner().exec(new OldAtan2Op(x, y, x.ulike()));
      }
docs: Atan2 operation, new INDArray instance will be returned
  Note the order of x and y parameters is opposite to that of java.lang.Math.atan2
  
  @param x the abscissa coordinate
  @param y the ordinate coordinate
  @return the theta from point (r, theta) when converting (x,y) from to cartesian to polar coordinates