Karim Belabas on Tue, 02 Oct 2007 17:08:21 +0200


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Re: some dilog values are complex instead of being real


* Vincent Lefevre [2007-10-02 10:15]:
> 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.

Indeed. Fixed in CVS [ development branch ]

Thanks !

    K.B.
-- 
Karim Belabas                  Tel: (+33) (0)5 40 00 26 17
Universite Bordeaux 1          Fax: (+33) (0)5 40 00 69 50
351, cours de la Liberation    http://www.math.u-bordeaux.fr/~belabas/
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