#10075: Make log gamma symbolic
---------------------------+------------------------------------------------
Reporter: kcrisman | Owner: burcin
Type: enhancement | Status: needs_review
Priority: major | Milestone: sage-5.0
Component: symbolics | Keywords: sd35.5
Work_issues: | Upstream: N/A
Reviewer: | Author: Karen T. Kohl
Merged: | Dependencies:
---------------------------+------------------------------------------------
Old description:
> Currently, there is no way to send `log_gamma` to Maxima, for instance.
> This can be fixed by following the models in the functions/ directory; it
> should be possible to make it a !GinacFunction. Before doing so, though,
> one will have to resolve #10072, since the evaluation will be wrong (?)
> otherwise.
New description:
Currently, there is no way to send `log_gamma` to Maxima, for instance.
This can be fixed by following the models in the functions/ directory; it
should be possible to make it a !GinacFunction. Before doing so, though,
one will have to resolve #10072, since the evaluation will be wrong (?)
otherwise.
Apply only [attachment:trac_10075_log_gamma_without_functions.rst.patch].
--
Comment(by kcrisman):
Since #9130 has positive review: Apply only
[attachment:trac_10075_log_gamma_without_functions.rst.patch].
One might think that Burcin's comment about `-2.1` makes this 'needs
work', but that is actually the current Sage behavior as well, so in
principle that would be a different ticket, since making `log_gamma`
symbolic would not introduce a regression...
In fact,
{{{
sage: log_gamma(-2.1)
NaN
sage: log_gamma(-3.1)
0.400311696703985
sage: log_gamma(-4.1)
NaN
sage: log_gamma(-5.1)
-2.63991581673655
sage: get_systems('log_gamma(2.1)')
['MPFR']
}}}
Apparently this is how MPFR deals with this function. So maybe all is
well?
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/10075#comment:9>
Sage <http://www.sagemath.org>
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