Hi there,
I am having a bit of trouble evaluating some multiple polylogarithms
using the latest version of GiNaC. GiNaC is giving me a different
response depending on whether I input the values as fractions or
decimals.
Specifically, I'm trying to find a floating point representation for
Li({1,1,2}, {1+1/2*I, 1, 3/5 - 4/5*I}). I've tried this by running (in
ginsh):
evalf(Li({1,1,2}, {1+1/2*I, 1, 3/5 - 4/5*I}));
but this seems to hang (I've run it for over 12 hours with no result).
On the other hand, running
evalf(Li({1,1,2}, {1+0.5*I, 1, 3/5 - 4/5*I}));
gives an answer almost immediately.
I've tried this using a C++ program (see attached) which behaves in
the same way: no result using the fraction but an answer with no
issues using a decimal number.
These calculations have been run using GiNaC 1.7.0 (stable & from git)
on ArchLinux.
Please let me know if there is anything I should try.
Peter
PS: I tried sending this email from a different address but it said it
was greylist - I apologise if I've sent this twice.