@Article{Graillat:2015:ECF, author = "Stef Graillat and Christoph Lauter and Ping Tak Peter Tang and Naoya Yamanaka and Shin'ichi Oishi", title = "Efficient calculations of faithfully rounded $l_2$-norms of $n$-vectors", journal = "{ACM} Transactions on Mathematical Software", volume = "41", number = "4", accepted = "1 November 2014", upcoming = "true", abstract = " In this paper, we present an efficient algorithm to compute the faithful rounding of the $l_2$-norm of a floating-point vector. This means that the result is accurate to within one bit of the underlying floating-point type. This algorithm does not generate overflows or underflows spuriously, but does so when the final result indeed calls for such a numerical exception to be raised. Moreover, the algorithm is well suited for parallel implementation and vectorization. The implementation runs up to 3 times faster than the netlib version on current rocessors.", }