let t1 = FFTComplex { re: in1.im + in0.im, im: in1.re - in0.re };
let tab = self.table[n];
let t2 = FFTComplex { re: t1.im * tab.im + t1.re * tab.re, im: t1.im * tab.re - t1.re * tab.im };
let t1 = FFTComplex { re: in1.im + in0.im, im: in1.re - in0.re };
let tab = self.table[n];
let t2 = FFTComplex { re: t1.im * tab.im + t1.re * tab.re, im: t1.im * tab.re - t1.re * tab.im };