On Jun 16, 2021, at 21:23, Joachim Wuttke via Boost
wrote: Is the difficulty with elliptic integrals discussed in any publication?
A very difficult subject. The "smoothness" and "parabolicity" of those is highly misleading. I would not expect any kind of polynomials to approximate elliptic integrals very well because the radius of convergence of normal power series for it is finite, and LESS THAN the range of the argument. From my experience with these functions, I would substract an approximant based on a pole-zero product expansion and build a polynomial approximand for the remainder. A classic paper is Luke in 1968: https://www.ams.org/journals/mcom/1968-22-103/S0025-5718-1968-0226825-3/S002... https://www.ams.org/journals/mcom/1968-22-103/S0025-5718-1968-0226825-3/S002... Cheers, Kostas