#20051: Singularity analysis: fix and speed up singularity analysis (log-type)
without renormalization
-----------------------------------------+------------------------
Reporter: cheuberg | Owner:
Type: defect | Status: new
Priority: major | Milestone: sage-7.1
Component: asymptotic expansions | Resolution:
Keywords: singularity analysis | Merged in:
Authors: Clemens Heuberger | Reviewers:
Report Upstream: N/A | Work issues:
Branch: | Commit:
Dependencies: #20020 | Stopgaps:
-----------------------------------------+------------------------
Changes (by {'newvalue': u'Clemens Heuberger', 'oldvalue': ''}):
* priority: minor => major
* author: => Clemens Heuberger
* type: enhancement => defect
Old description:
> #20020 introduced
> `asymptotic_expansions._SingularityAnalysis_non_normalized_`. Its
> performance is poor as it relies on substitution. Speed up is possible by
> introducing a flag to `asymptotic_expansions.SingularityAnalysis` to
> ignore the normalization factor.
>
> See #17601 for the asymptotic expansions meta ticket.
New description:
#20020 introduced
`asymptotic_expansions._SingularityAnalysis_non_normalized_`.
For `zeta != 1`, its results are incorrect due to substitution:
{{{
sage: asymptotic_expansions._SingularityAnalysis_non_normalized_(
....: 'n', 1/2, alpha=0, beta=1, precision=3)
1/2*2^n*n^(-1) + O(2^n*n^(-2))
}}}
instead of the correct `2^n * n^(-1) + O(2^n * n^(-2))`.
Furthermore, its performance is poor as it relies on substitution. Speed
up is possible by introducing a flag to
`asymptotic_expansions.SingularityAnalysis` to ignore the normalization
factor.
See #17601 for the asymptotic expansions meta ticket.
--
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Ticket URL: <http://trac.sagemath.org/ticket/20051#comment:1>
Sage <http://www.sagemath.org>
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