Hello Tim, I just wanted to let you know that when you work with DoubleFloat you can use a trick : if you set $useBFasDefault to false the Spad compiler will handle floating point numbers as DoubleFloat directly, no need to coerce them. So you just have to add ')boot $useBFasDefault := false' at the beginning of the file (and re-set $useBFasDefault to true at the end of the file). Not a beautiful hack though.
Greg Le vendredi 01 février 2008 à 08:50 -0600, [EMAIL PROTECTED] a écrit : > This patch adds the numeric calculation of the principal value of > the Exponential Integral function. This is defined by a 6 segment > piecewise approximation using Chebyshev polynomials. In addition > to the main function Ei, each of the 6 piecewise solutions can be > gotten directly by the EiN functions, which are also exposed. The > EiN functions are normalized to return results in -1 <= x <= 1. > > Ei (-\infty < x < \infty) > > Ei1 (-\infty < x < -10) using xe^xEi(x) > Ei2 (-10 <= x <= -4) using xe^xEi(x) > Ei3 (-4 <= x <= 4) using (Ei(x)-log(abs(x))-\gamma)/x > Ei4 (4 <= x <= 12) using xe^xEi(x) > Ei5 (12 <= x <= 32) using xe^xEi(x) > Ei6 (32 <= x < /infty) using xe^xEi(x) > > The approximation is valid for 10^-30 but the implementation using > DoubleFloat does about 10^-16. The full coefficients are retained > for a future gmp implementation. > _______________________________________________ Axiom-developer mailing list [email protected] http://lists.nongnu.org/mailman/listinfo/axiom-developer
