Opened 9 years ago
Closed 9 years ago
#12303 closed defect (duplicate)
leave beta symbolic for exact complex inputs
Reported by: | ktkohl | Owned by: | burcin |
---|---|---|---|
Priority: | major | Milestone: | sage-duplicate/invalid/wontfix |
Component: | symbolics | Keywords: | beta special function |
Cc: | benjaminfjones, kcrisman | Merged in: | |
Authors: | Reviewers: | Burcin Erocal | |
Report Upstream: | N/A | Work issues: | |
Branch: | Commit: | ||
Dependencies: | Stopgaps: |
Description
Ticket #9130 implements access to the beta function. But exact complex inputs result in a numerical output from ginac.
beta(2,1+5*I) -0.0305039787798408 - 0.0198938992042440*I
Change History (8)
comment:1 Changed 9 years ago by
- Cc benjaminfjones added
comment:2 follow-up: ↓ 3 Changed 9 years ago by
comment:3 in reply to: ↑ 2 Changed 9 years ago by
- Dependencies 9130 deleted
- Milestone changed from sage-5.0 to sage-5.1
Pynac 0.2.4 from #12950 contains a fix for this. There is a patch with a doctest attached to that ticket. We should close this when that is merged.
Replying to benjaminfjones:
How is a Ginac function called to do numerical evaluation? I thought this would work as a custom
_eval_
method forbeta
:def _eval_(self, y, z): if not isinstance(y, Expression) and not isinstance(z, Expression) and \ (is_inexact(y) or is_inexact(z)): coercion_model = sage.structure.element.get_coercion_model() y, z = coercion_model.canonical_coercion(y, z) return GinacFunction.__call__(self, y, z) return NoneBut
GinacFunction.__call__
ends up calling the custom_eval_
and I get an infinite recursion. I'm having trouble using the debugger to determine how, for example,beta(4.0, 5.0)
is calculated. Is this because Pynac is mostly in Cython?
Pynac is mostly C++. You should use GDB to trace the code.
The short answer to your question is: I haven't thought of this use case, so there isn't an easy way to call the evaluation method defined in Pynac from your _eval_()
. The custom methods can only overwrite the ones defined in C++, they don't follow any inheritance principles from OOP.
This could be done by calling beta_eval()
defined in ginac/inifcns_gamma.cpp
directly from Cython, but that would be really messy. :)
comment:4 Changed 9 years ago by
Ok, that makes sense. Thanks. I'll have a look at #12950.
comment:5 Changed 9 years ago by
- Cc kcrisman added
comment:6 Changed 9 years ago by
- Milestone changed from sage-5.1 to sage-duplicate/invalid/wontfix
- Reviewers set to Burcin Erocal
- Status changed from new to needs_review
This can be closed since #12950 was merged.
comment:7 Changed 9 years ago by
- Status changed from needs_review to positive_review
comment:8 Changed 9 years ago by
- Keywords beta added
- Resolution set to duplicate
- Status changed from positive_review to closed
How is a Ginac function called to do numerical evaluation? I thought this would work as a custom
_eval_
method forbeta
:But
GinacFunction.__call__
ends up calling the custom_eval_
and I get an infinite recursion. I'm having trouble using the debugger to determine how, for example,beta(4.0, 5.0)
is calculated. Is this because Pynac is mostly in Cython?