Re: Handling branch cuts for hypergeometric functions

Robert Dodier wrote:

> Hello Ray, you wrote in part:
> 
> 
>>Would it make sense to just ask the user if 0 < x < 1 and use
>>15.4.13, otherwise use 15.4.12?  This kind of implies to the
>>user that x is a real number.
> 
> 
> I'm mostly against the use of interactive queries, as their
> presence makes it difficult to write noninteractive programs
> (e.g. batch files).
> 
Since maxima already uses interactive queries, it would be
more consistent to have more interactive queries.
On the other hand, it is also consistent to have flags
of some sort that make default assumption.  So my suggestion
is,  if it is not too much trouble, to have a flag to set
that controls this behavior.

In answers produced by Tilu, we provide unevaluated conditionals
as the answers to some integrals, and leave it to the recipient
to work out the final results.


> An appropriate result here would be an unevaluated
> conditional representing the possible choices, perhaps with
> all alternatives evaluated or all unevaluated or some mix
> such as evaluating only the alternative with the simplest
> assumptions.
> 
> Until we reach the distant Utopia of unevaluated conditionals,
> my vote is for making the simplest assumption that can't be
> disproven according to the assume database. In this case that
> might be to assume x is real.
> 
> Thanks a lot for all your work. I know you've put a lot
> of effort into the hypergeometric functions package.
> 
> Hope this helps,
> Robert Dodier
> 
> 
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