Yigal, On January 26, 2006 6:19 PM you wrote: > > Yes, I didn't realize the power of Axiom, I simply made the > function, > > gamma(n,x) == factorial(n-1)*exp(-x)* > reduce(+, [x^i/factorial(i) for i in 0..(n-1)]) > > which was adapted from the example function in the book, > > f(n) == reduce(*,[i for i in 2..n]) > > sorry for the lame question I am just beginning to use Axiom, >
I don't think your question was "lame" at all. The evaluation of the incommplete Gamma function as a floating point value is something that *should* be built in to Axiom. In general I think even Axiom's treatment of Gamma is a little "uneven". In fact the whole area of special functions in Axiom is due for a major overhaul... See for example: http://wiki.axiom-developer.org/6WrongIntegrationResult http://wiki.axiom-developer.org/130SpecialFunctionIntegerDoesntReturnExpress ionInteger Anyway, here is another "one-liner" for Gamma, more or less equivalent to the function you wrote, which illustrates some of the other "power" of Axiom: gamma2(a,z) == integrate(exp(-t)*t^(a-1), t=(z::POLY FRAC INT)..%plusInfinity)::Expression Float Regards, Bill Page. _______________________________________________ Axiom-math mailing list [email protected] http://lists.nongnu.org/mailman/listinfo/axiom-math
