On Tue, Mar 13, 2012 at 12:35 AM, Andrej Vodopivec <
andrej.vodopivec at gmail.com> wrote:
>
> simplify_sum finds that this sum equals 2/3*hypergeometric([-1/2,
> 3/4],[7/4],-1). The error comes from hgfred:
>
> (%i1) 2/3*hgfred([-1/2,3/4],[7/4],-1);
> expt: undefined: 0 to a negative exponent.
> -- an error. To debug this try: debugmode(true);
>
Curious. I was getting this error too. But then I went and recompiled
src/hyp.lisp and the error went away. I now get
(%i16) hgfred([-1/2,3/4],[7/4],-1);
SIMP2F1-WILL-CONTINUE-IN
(%o16) %f[2,1]([-1/2,3/4],[7/4],-1)
I don't always recompile everything from scratch, so there must be some bad
interaction between compiling parts of maxima and loading an old hyp.fasl.
What that could be, I don't know. Perhaps some issue with special
variables. (There are quite a few in hyp and hypgeo.)
Ray