evaluating erf(%i) in maxima



>>>>> "Seth" == Seth Goldberg  writes:

    Seth> How this arose.
    Seth> I was noodling around and asked for 
    Seth> integrate(sin(x^2),x);
    Seth> I got back some interesting form in terms of erf 
    Seth> (as an alternative to the usual textbook form). 
    Seth> This checked out OK on differentiation.
    Seth> However, it wouldn't plot, and wouldn't evaluate for x=1.
    Seth> Using rectform or ev(...,numer) doesn't seem to help.

    Seth> The problem seems already present in erf(%i)

This is a deficiency in maxima.  It doesn't know how to calculate erf
for complex args.

I've looked around for an algorithm to do this, but haven't found one
yet.  There was a patch for octave that used Rybicki's method for
complex args, but it had some unexplained constants that I wanted to
understand, and my local university library didn't seem to have the
journal with Rybicki's article, so I didn't do anything about it.

File this as a bug, if you like.

Ray