#17066: always simplify hypergeometric() when it's a polynomial
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Reporter: rws | Owner:
Type: defect | Status: needs_review
Priority: major | Milestone: sage-6.4
Component: symbolics | Resolution:
Keywords: special, | Merged in:
functions, pFq, evaluation | Reviewers:
Authors: Ralf Stephan | Work issues:
Report Upstream: N/A | Commit:
Branch: | 55daf81080f46c54429e629b65e8049acfdb6d00
u/rws/work_around_mpmath_problem_with_hypergeometric___zeroes| Stopgaps:
Dependencies: |
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Comment (by mmezzarobba):
Expanding hypergeometric functions in polynomial closed form before
evaluating them can lead to numerical cancellation. Compare for example
{{{
sage: hypergeometric([1,-100],[3], 0.7)
0.0278923450568346
sage: hypergeometric([1,-100],[3], Reals(1000)(0.7)).n()
0.0278923450568346
sage:
sage.functions.hypergeometric.closed_form(hypergeometric([1,-100],[3],x)).subs(x=0.7)
-376.859920391941
}}}
Won't that be a problem with this ticket? (I didn't read beyond the
ticket's description, so please ignore my comment if it is beside the
point.)
--
Ticket URL: <http://trac.sagemath.org/ticket/17066#comment:16>
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