fft: complex-data, 2D transforms
	genial float	fftw estimate float	fftw measure float	genial double	fftw estimate double	fftw measure double
(4x4)	1301	1379	1412	917	1459	1466	
(8x8)	2952	3378	3431	1833	2642	2650	
(8x16)	3691	4265	4253	2217	3036	3035	
(16x16)	4405	5299	5230	2607	3663	3634	
(16x32)	4681	4772	4750	2928	3212	3191	
(32x32)	4757	4399	4427	2793	3137	3118	
(32x64)	5139	4213	4965	2442	2400	2780	
(64x64)	4903	3831	4623	2457	2251	2395	
(64x128)	4754	4546	4755	2217	2372	2443	
(128x128)	4459	2547	3773	2019	1549	2256	
(128x256)	3981	2512	3561	1598	1275	1838	
(256x256)	3691	2375	3314	1012	786	996	
(256x512)	2095	1504	1794	307	145	582	
(512x512)	549	503	1321	236	170	549	
(1024x1024)	508	524	1238	234	154	447