docs: def reshape_to_2d(arr):
    '''
    Assumes a 3D Numpy array, and reshapes like
    
    arr.reshape((arr.shape[0], arr.shape[1]*arr.shape[2]))
  
    This is useful for converting processed data from `complex_to_power`
    and from `autocorrelation` into a 2D array for image analysis and display.
  
    '''
    return arr.reshape((arr.shape[0], arr.shape[1]*arr.shape[2]))