a Instituto Superior de Engenharia de Coimbra, Quinta da Nora, 3030 Coimbra, Portugal
b Departamento de Matemática, Universidade de Coimbra, 3000 Coimbra, Portugal
Abstract:
We show that for a vast class of matrix Lie groups, which includes the orthogonal and the symplectic, diagonal Padé approximants of log((1+x)/(1−x)) are structure preserving. The conditioning of these approximants is analyzed. We also present a new algorithm for the Briggs–Padé method, based on a strategy for reducing the number of square roots in the inverse scaling and squaring procedure.