Opened 9 years ago
Closed 9 years ago
#8864 closed enhancement (fixed)
make zeta function symbolic
Reported by: | zimmerma | Owned by: | AlexGhitza |
---|---|---|---|
Priority: | major | Milestone: | sage-4.4.4 |
Component: | symbolics | Keywords: | |
Cc: | Merged in: | sage-4.4.4.alpha0 | |
Authors: | Burcin Erocal | Reviewers: | Paul Zimmermann |
Report Upstream: | N/A | Work issues: | |
Branch: | Commit: | ||
Dependencies: | Stopgaps: |
Description
Consider:
sage: zeta(3) 1.20205690315959
We expect zeta(3)
as answer.
Attachments (2)
Change History (8)
comment:1 Changed 9 years ago by
Changed 9 years ago by
comment:2 Changed 9 years ago by
- Component changed from basic arithmetic to symbolics
- Status changed from new to needs_review
With attachment:trac_8864-symbolic_zeta.patch you can do this:
sage: zeta(3) zeta(3) sage: zeta(2) 1/6*pi^2
Probably, the changes to sage/symbolic/random_tests.py
depend on #6949.
comment:3 Changed 9 years ago by
- Reviewers set to Paul Zimmermann
- Status changed from needs_review to needs_work
I applied that patch to 4.4.1. The new behaviour is ok, I get only one doctest failure in
lfunctions/dokchitser.py
. With 4.4.1 we got:
sage: h = RR('0.0000000000001') sage: (zeta(2+h) - zeta(2))/h -0.937028232783632
With the patch, we get:
sage: h = RR('0.0000000000001') sage: (zeta(2+h) - zeta(2))/h -1.66666666666667e12*pi^2 + 1.64493406684813e13
I guess the doctest result has to be changed, or zeta(2) changed to zeta(2.), since Sage does not
automatically propagate floats, for example pi+1.0
remains unchanged.
comment:4 Changed 9 years ago by
- Status changed from needs_work to needs_review
I uploaded attachment:trac_8864-symbolic_zeta.take2.patch which also includes a fix for the lfunctions/dokchitser.py
doctest. I simply replaced zeta(2)
with zeta(2)
to get a numeric evaluation.
I agree that pi+1.0
looks strange, but that is not so trivial to fix. :) FWIW, maple also seems to leave that unevaluated:
|\^/| Maple 12 (IBM INTEL LINUX) ._|\| |/|_. Copyright (c) Maplesoft, a division of Waterloo Maple Inc. 2008 \ MAPLE / All rights reserved. Maple is a trademark of <____ ____> Waterloo Maple Inc. | Type ? for help. > Pi +1.0; Pi + 1.0 > 1.0*Pi; 1.0 Pi
comment:5 Changed 9 years ago by
- Status changed from needs_review to positive_review
All tests pass now. Thus a positive review. Good work!
Paul
comment:6 Changed 9 years ago by
- Merged in set to sage-4.4.4.alpha0
- Resolution set to fixed
- Status changed from positive_review to closed
Note: this is a followup of #7748.