On Friday, September 26, 2014 4:25:58 PM UTC+2, Nils Bruin wrote:
>
> It would be good if mpmath used a different approach when it's known a 
> hypergeometric function is a polynomial, but it's a little orthogonal to 
> what happens in sage. By the time we hit mpmath, we're doing multiprecision 
> float computation. Polynomial hypergeometric functions can easily be 
> evaluated at arbitrary inputs (rational, algebraic, symbolic). We should 
> not be bothering with multiprecision floats if we don't have to, or at 
> least only do so if there's a benefit and we can control precision issues. 
>

In most symbolic special functions we check for special values and, if 
found, evaluate immediately. This is not so in hypergeometric.py but would 
be trivial to add. I can only speculate that the reason was the then forced 
call of maxima. Since this doesn't seem a problem with commenters please 
review

http://trac.sagemath.org/ticket/17066

and this can be simply emulated until inclusion of the ticket by saying

sage: hypergeometric([-2,-1],[2],-1).simplify_hypergeometric()
0

No need to explicitly call Maxima here.

Regards,

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