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. |