Vincent Lefevre on Tue, 02 Oct 2007 10:15:14 +0200


[Date Prev] [Date Next] [Thread Prev] [Thread Next] [Date Index] [Thread Index]

some dilog values are complex instead of being real 

Hi,

With Pari 2.3.2:

? dilog(-1)
%1 = -0.8224670334241132182362075834 + 9.136285398175292265776793780 E-29*I

but the value should be a real number. I suppose that the imaginary
term is due to a rounding error, in which case it should be zeroed
if one knows that the mathematical result is a real number.

Note that due to this problem, the plot function fails with:
  *** plot: impossible assignment t_COMPLEX --> t_REAL.

-- 
Vincent Lefèvre <vincent@vinc17.org> - Web: <http://www.vinc17.org/>
100% accessible validated (X)HTML - Blog: <http://www.vinc17.org/blog/>
Work: CR INRIA - computer arithmetic / Arenaire project (LIP, ENS-Lyon)