[ 1 1 1 ][y0]   [ y0 + y1 + y2      ]
[ 1 w w*][y1] = [ y0 + wy1 + (wy2)* ]
[ 1 w* w][y2]   [ y0 + (wy1)* + wy2 ]

Best can do with 'just' complex ops (no using real/imag parts seperately) is 2 complex *'s and 6 complex +'s

But with using real/imag parts seperaretly, and working with them seperately, can do it in 4 *'s and 14 +'s

2 complex * and 6 complex + works out as: 16 +'s and 8 *'s