Stable computation of the complex roots of unity

Shows that the problem of computing the complex roots of unity is not as simple as it seems at first. In particular, the formulas given in a standard programmer´s reference book (Knuth, Seminumerical Algorithms, 1981) are shown to be numerically unstable, giving unacceptably large error for moderate sized sequences. The author gives alternative formulas, which are shown to be superior both by analysis and experiment