Dear all, this is a bug fix for the bug reported in http://www.cebix.net/pipermail/ginac-list/2015-July/002053.html The bug occured because a call to ex_to<numeric>(y) inside the polylog routines would fail for y=sqrt(2), resulting in a sub-sequent segmentation fault. In GiNaC sqrt(2) is treated as an exact number, not as a floating number. With the fix, the routine now returns unevaluated (as it should). An explicit call to evalf() forces a conversion to floats. In order to enable this, the option do_not_evalf_params() has been removed for the G-functions. This is safe for the G-functions, the purpose of the do_not_evalf_params-option is to avoid a conversion of genuine integer arguments (as in Li, S, H, zeta1 or zeta2) to floats. Best wishes, Stefan