Yes, we can adjust the result in all cases we know that it is pure real or pure
imaginary. We have implemented this for the Bessel functions.
I will have a look at this topic.
Dieter Kaiser
-----Urspr?ngliche Nachricht-----
Von: robert.dodier at gmail.com [mailto:robert.dodier at gmail.com]
Gesendet: Dienstag, 23. Dezember 2008 07:10
An: Dieter Kaiser
Cc: maxima at math.utexas.edu
Betreff: Re: [Maxima] Maxima 5.17.1 regressions for Sage
On 12/22/08, Dieter Kaiser <drdieterkaiser at web.de> wrote:
> Thus, I do not think that we have errors in Maxima, but Sage get unexpected
> results for the erf function with complex arguments.
>
> Remark: We have small realparts in the results. This is due to the limited
> numerical accuracy of the routine.
It seems reasonable that if the result is known to be be real for all
arguments in some set of arguments, that a computed numerical
approximation should likewise be real. Can't the numerical function
just return realpart(whatever) when the argument is known to yield
a real result?
best
Robert