def _pol_to_cart(pol):
 out = np.empty_like(pol)
 out[:, 0] = (pol[:, 0] * np.cos(pol[:, 1]))
 out[:, 1] = (pol[:, 0] * np.sin(pol[:, 1]))
 return out

def _pol_to_cart ( pol ) : out = np . empty_like ( pol ) out [ : , 0 ] = ( pol [ : , 0 ] * np . cos ( pol [ : , 1 ] ) ) out [ : , 1 ] = ( pol [ : , 0 ] * np . sin ( pol [ : , 1 ] ) ) return out
transform polar coordinates to cartesian .