SIMBAD references

We present a code for the fast computation of the Lomb-Scargle periodogram that uses nonequispaced fast Fourier transforms (FFTs). The computation time has the classical O(NlogN) behaviour of FFTs, but is shorter by about one order of magnitude than the ``classical'' fast algorithm by Press and Rybicki, and is about five times shorter that the best GPU-based implementations of the usual O(N²) algorithm. This performance is achieved without sacrificing accuracy, as revealed by comparing the computations done with our FFT-based algorithm and a naieve one.