Re: erfc(0) yields error

[Karim Belabas <Karim.Belabas@math.u-psud.fr>]

* D. Hugh Redelmeier [2004-02-24 06:52]:
> I'm trying to use erfc, the complementary error function in a little
> gp program that I'm writing.  I'm very new to pari/gp, but I think
> that I've found a bug.
> 
> It seems to me that the complementary error function is mathematically
> well-defined at 0.  It ought to be 1.  And yet, gp doesn't like 0:
> 
>     ? erfc(0)
>       ***   incorrect type in negation.
>     ? erfc(0.0)
>       ***   incorrect type in negation.
>     ? erfc(0.0000000000000000001)
>     %2 = 0.9999999999999999998871620833
> 
> The error message is a little opaque too.
> 
> Version information:
> 
>                    GP/PARI CALCULATOR Version 2.2.7 (alpha)
>                 i686 running linux (ix86 kernel) 32-bit version
>        compiled: Feb 17 2004, gcc-3.2 20020903 (Red Hat Linux 8.0 3.2-7)

I have fixed the problem in CVS  ( it was an internal error, nothing faulty
about the error message: the routine indeed received an invalid object )

Thanks for the bug report !

Cheers,

    Karim.
-- 
Karim Belabas                     Tel: (+33) (0)1 69 15 57 48
Dep. de Mathematiques, Bat. 425   Fax: (+33) (0)1 69 15 60 19
Universite Paris-Sud              http://www.math.u-psud.fr/~belabas/ 
F-91405 Orsay (France)            http://pari.math.u-bordeaux.fr/  [PARI/GP]