fft: complex-data, 2D transforms
	genial float	fftw estimate float	fftw measure float	genial double	fftw estimate double	fftw measure double
(4x4)	422	1388	1384	341	1394	1413	
(8x8)	1401	3348	3334	983	2597	2586	
(8x16)	2133	4234	4255	1437	3005	2985	
(16x16)	2856	5181	5124	1902	3660	3632	
(16x32)	3597	4826	4773	2215	3029	3020	
(32x32)	4005	4694	4660	2413	2978	2767	
(32x64)	4347	4091	4981	2172	2427	2803	
(64x64)	4351	3929	4703	2203	2191	2318	
(64x128)	4464	4536	4791	2118	2349	2515	
(128x128)	4403	2552	3803	1978	1562	2330	
(128x256)	4099	2487	3507	1534	1251	1851	
(256x256)	3492	2352	3251	980	781	1001	
(256x512)	2061	1482	1738	259	145	624	
(512x512)	519	488	1321	248	178	617	
(1024x1024)	530	524	1219	276	172	629