public static extern IntPtr r2r_3d( int nx, int ny, int nz, IntPtr input, IntPtr output, InteropFFTWKind kindx, InteropFFTWKind kindy, InteropFFTWKind kindz, InteropFFTWFlags flags);
public static extern IntPtr r2r_1d(int n, IntPtr input, IntPtr output, InteropFFTWKind kind, InteropFFTWFlags flags);
public static extern IntPtr r2r(int rank, int[] n, IntPtr input, IntPtr output, InteropFFTWKind[] kind, InteropFFTWFlags flags);