Opened 8 years ago
Closed 6 years ago
#16203 closed defect (fixed)
conversion from SR.series to PowerSeries
Reported by: | rws | Owned by: | |
---|---|---|---|
Priority: | major | Milestone: | sage-7.2 |
Component: | algebra | Keywords: | series conversion days71 |
Cc: | kcrisman | Merged in: | |
Authors: | Ralf Stephan | Reviewers: | Maurizio Monge, Marc Mezzarobba |
Report Upstream: | N/A | Work issues: | |
Branch: | aa9c05c (Commits, GitHub, GitLab) | Commit: | aa9c05c65a43fc26d947dfadcdc7fe77156a614e |
Dependencies: | #17399, #17438, #17659 | Stopgaps: |
Description (last modified by )
sage: R.<x> = PowerSeriesRing(SR) sage: var('y') y sage: ex=1/(1-y) sage: ex.series(y,20) 1 + 1*y + 1*y^2 + 1*y^3 + 1*y^4 + 1*y^5 + 1*y^6 + 1*y^7 + 1*y^8 + 1*y^9 + 1*y^10 + 1*y^11 + 1*y^12 + 1*y^13 + 1*y^14 + 1*y^15 + 1*y^16 + 1*y^17 + 1*y^18 + 1*y^19 + Order(y^20) sage: s=R(_); s 1 + y + y^2 + y^3 + y^4 + y^5 + y^6 + y^7 + y^8 + y^9 + y^10 + y^11 + y^12 + y^13 + y^14 + y^15 + y^16 + y^17 + y^18 + y^19 + Order(y^20) sage: type(s) <type 'sage.rings.power_series_poly.PowerSeries_poly'> sage: s.list() [1 + 1*y + 1*y^2 + 1*y^3 + 1*y^4 + 1*y^5 + 1*y^6 + 1*y^7 + 1*y^8 + 1*y^9 + 1*y^10 + 1*y^11 + 1*y^12 + 1*y^13 + 1*y^14 + 1*y^15 + 1*y^16 + 1*y^17 + 1*y^18 + 1*y^19 + Order(y^20)]
The correct result would be 1 + x + x^2...
. Obviously Order(20)
is not recognized as a marker for the existence of a power series. The whole symbolic expression is taken as a constant.
Also reported in http://ask.sagemath.org/question/24777/how-to-convert-a-taylor-polynomial-to-a-power-series/ and http://ask.sagemath.org/question/24968/coefficients-in-polynomial-ring-over-symbolic-ring/
Change History (29)
comment:1 Changed 8 years ago by
- Milestone changed from sage-6.2 to sage-6.3
comment:2 Changed 8 years ago by
- Milestone changed from sage-6.3 to sage-6.4
comment:3 Changed 8 years ago by
- Description modified (diff)
comment:4 Changed 7 years ago by
- Description modified (diff)
comment:5 Changed 7 years ago by
- Cc kcrisman added
comment:6 Changed 7 years ago by
- Branch set to u/rws/conversion_from_sr_series___to_powerseries_sr__gives_unexpected_result
comment:7 Changed 7 years ago by
- Commit set to 0a43e2185b5a218184ee64dc2f2a3d6d4c4d0de6
- Dependencies set to #17399, #17438
comment:8 Changed 7 years ago by
- Branch u/rws/conversion_from_sr_series___to_powerseries_sr__gives_unexpected_result deleted
- Commit 0a43e2185b5a218184ee64dc2f2a3d6d4c4d0de6 deleted
comment:9 Changed 7 years ago by
- Branch set to public/16203
comment:10 Changed 7 years ago by
- Commit set to 53b2ca4e5f0c07c2c4e16d6fc6ee71f15ad29093
- Status changed from new to needs_review
- Summary changed from conversion from SR.series() to PowerSeries(SR) gives unexpected result to conversion from SR.series to PowerSeries
This also resolves #16198
New commits:
32ae67c | 17399: do not let maxima handle ex.series coefficients
|
99820cf | 17399: roll back previous commit to allow merge of 17428
|
d7da52c | 17438: implement coeff list
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9452fa9 | 17438: deprecate ex.coeff/coeffs()
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0fec129 | 17438: implement ex.list()
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168b659 | Merge branch 'u/rws/coefficients_of_symbolic_expressions_revamp' of trac.sagemath.org:sage into t/17399/fix_coefficients_for_symbolic_series
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6cd5286 | 17399: handle series in ex.coefficients()
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53b2ca4 | 16203: implement conversion SR.series --> PowerSeries
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comment:11 follow-up: ↓ 12 Changed 7 years ago by
As currently stated in the description, this is the correct result as the variable for PowerSeriesRing
is x
, whereas we have some symbolic expression in y
(so is naturally an element in the coefficient ring). Having mismatched variable names automatically converting over seems fraught with problems and could lead to subtle bugs.
comment:12 in reply to: ↑ 11 Changed 7 years ago by
Replying to tscrim:
As currently stated in the description, this is the correct result as the variable for
PowerSeriesRing
isx
, whereas we have some symbolic expression iny
(so is naturally an element in the coefficient ring). Having mismatched variable names automatically converting over seems fraught with problems and could lead to subtle bugs.
I see. So, conversion to an existing power series ring should only be allowed if the series expansion variable has the same name as the ring var. Multiple vars aren't supported by SR.series anyway.
comment:13 Changed 7 years ago by
- Commit changed from 53b2ca4e5f0c07c2c4e16d6fc6ee71f15ad29093 to e1a90393ca47a2f057cd43231b8f67ec05443748
Branch pushed to git repo; I updated commit sha1. New commits:
e1a9039 | 16203: implement ex.series_variable; disallow ex.series conversion into mismatched PowerSeries ring element
|
comment:14 Changed 7 years ago by
comment:15 Changed 7 years ago by
- Branch changed from public/16203 to public/16203-1
comment:16 Changed 7 years ago by
- Commit changed from e1a90393ca47a2f057cd43231b8f67ec05443748 to 3ece975a59933edd7e742dbdc665ab85e1f9dafb
- Dependencies changed from #17399, #17438 to #17399, #17438, #17659
New commits:
3ece975 | 16203: conversion from SR.series to PowerSeries
|
comment:17 Changed 7 years ago by
- Commit changed from 3ece975a59933edd7e742dbdc665ab85e1f9dafb to 84bc4fb0a28b4094da5fc130d08de00e862bd2a0
comment:18 Changed 7 years ago by
- Commit changed from 84bc4fb0a28b4094da5fc130d08de00e862bd2a0 to 1d363e0f7758d02b6d36ad968016ce68a50919d1
Branch pushed to git repo; I updated commit sha1. New commits:
1d363e0 | 16203: fixes
|
comment:19 Changed 7 years ago by
- Commit changed from 1d363e0f7758d02b6d36ad968016ce68a50919d1 to 50cb33cc5e93de8679d7b4c7e2134320ca462a6f
Branch pushed to git repo; I updated commit sha1. New commits:
50cb33c | Merge branch 'develop' into t/16203/public/16203-1
|
comment:20 Changed 7 years ago by
- Milestone changed from sage-6.4 to sage-pending
Pending because #17659 is pending.
comment:21 Changed 6 years ago by
- Branch changed from public/16203-1 to public/16203-2
comment:22 Changed 6 years ago by
- Commit changed from 50cb33cc5e93de8679d7b4c7e2134320ca462a6f to 9cb0cc909988327b9a4a94e20743e95fbccae11c
- Milestone changed from sage-pending to sage-7.2
New commits:
9cb0cc9 | Merge branch 'public/16203-1' of trac.sagemath.org:sage into tmp06
|
comment:23 Changed 6 years ago by
- Keywords days71 added
- Reviewers set to Maurizio Monge
- Status changed from needs_review to needs_work
"is" should be "==". The changes to ring.pyx are unrelated and should be removed. Everything else looks alright.
comment:24 Changed 6 years ago by
- Branch changed from public/16203-2 to public/16203-3
comment:25 Changed 6 years ago by
- Commit changed from 9cb0cc909988327b9a4a94e20743e95fbccae11c to ec8c797a4c57ac144d23c93749ad2e6f7ca5f9c7
- Status changed from needs_work to needs_review
New commits:
ec8c797 | 16203: conversion from SR.series to PowerSeries
|
comment:26 Changed 6 years ago by
- Commit changed from ec8c797a4c57ac144d23c93749ad2e6f7ca5f9c7 to aa9c05c65a43fc26d947dfadcdc7fe77156a614e
Branch pushed to git repo; I updated commit sha1. New commits:
aa9c05c | 16203: fix string cmp
|
comment:27 Changed 6 years ago by
- Reviewers changed from Maurizio Monge to Maurizio Monge, Marc Mezzarobba
- Status changed from needs_review to positive_review
comment:28 Changed 6 years ago by
Thanks!
comment:29 Changed 6 years ago by
- Branch changed from public/16203-3 to aa9c05c65a43fc26d947dfadcdc7fe77156a614e
- Resolution set to fixed
- Status changed from positive_review to closed
New commits:
17399: do not let maxima handle ex.series coefficients
16203: preliminary implementation, dependent on 17399, 17438