cores: cputime/grid p./time st. scaling:	grid
1      4.07                     -	64x64x64    
2      2.08                     1.96	64x128x64   
4      1.04                     2.00	64x128x128  
8      0.484                    2.15	128x128x128 
16     0.240                    2.02	128x256x128 
32     0.123                    1.95	128x256x256 
64     0.0596                   2.06	256x256x256 
128    0.0300                   1.99	256x512x256 
256    0.0158                   1.90	256x512x512 
512    0.00862                  1.83`	512x512x512