 There is a trade-off in that there may be some loss of precision when using floating point.For fast Fourier transforms (FFTs) (or any linear transformation) the complex multiplies are by constant coefficients "c" + "di" (called twiddle factors in FFTs), in which case two of the additions ("d"−"c" and "c"+"d") can be precomputed.Hence, only three multiplies and three adds are required.