These constants define the different scaling methods for the result of Fast Fourier Transform (FFT).

Values:

IG_FFT_SCALING_UNITY	0	Unity scaling, i.e., no scaling on the result.
IG_FFT_SCALING_N	1	Scale by 1/N on each dimension.
IG_FFT_SCALING_SQRTN	2	Scale by 1/sqrt(N) on each dimension.