[GiNaC-devel] Numerical evaluation for tgamma, lgamma and beta.

[Chris Dams]

Dear all, 

I added numerical evaluation for the functions tgamma, lgamma and beta to 
the CVS. The method employed is the Lanczos approximation as described on 
Wikepedia: http://en.wikipedia.org/wiki/Lanczos_approximation . (I also 
corrected some small errors on that page.)

This method uses a fixed precision and tables are used to store 
coefficients. Currently the tables available are for maximally 20, 50, 100 
and 200 digits. If Digits exceeds 200, no numerical evaluation is 
available.

Best wishes,
Chris