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@0sidharth 0sidharth commented Sep 29, 2021

References to other Issues or PRs

Fixes #22181

Brief description of what is fixed or changed

Previously, (-1)**(1/n) (1/n as sympy substitutes to bring n->0) is rewritten as exp(I*pi/n) and 2**(1/n) is rewritten as exp(log(2)/n) which leads to the NotImplementedError with (-log(2) + I*pi).
Now the expression is first powsimplified in case it is a Mul with z0 as infinite.

Release Notes

  • series
    • Fixed a bug due to insufficient power simplification in limits

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sympy-bot commented Sep 29, 2021

Hi, I am the SymPy bot (v161). I'm here to help you write a release notes entry. Please read the guide on how to write release notes.

Your release notes are in good order.

Here is what the release notes will look like:

  • series
    • Fixed a bug due to insufficient power simplification in limits (#22182 by @0sidharth)

This will be added to https://github.com/sympy/sympy/wiki/Release-Notes-for-1.10.

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#### References to other Issues or PRs
<!-- If this pull request fixes an issue, write "Fixes #NNNN" in that exact
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Fixes #22181 

#### Brief description of what is fixed or changed
Previously, `(-1)**(1/n)` (1/n as sympy substitutes to bring n->0) is rewritten as `exp(I*pi/n)` and `2**(1/n)` is rewritten as `exp(log(2)/n)` which leads to the `NotImplementedError` with `(-log(2) + I*pi)`.
Now the expression is first `powsimp`lified in case it is a `Mul` with `z0` as infinite.

#### Release Notes

<!-- Write the release notes for this release below between the BEGIN and END
statements. The basic format is a bulleted list with the name of the subpackage
and the release note for this PR. For example:

* solvers
  * Added a new solver for logarithmic equations.

* functions
  * Fixed a bug with log of integers.

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<!-- BEGIN RELEASE NOTES -->
* series
  * Fixed a bug due to insufficient power simplification in limits
<!-- END RELEASE NOTES -->

Update

The release notes on the wiki have been updated.

@0sidharth 0sidharth requested a review from jksuom September 29, 2021 17:24
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Benchmark results from GitHub Actions

Lower numbers are good, higher numbers are bad. A ratio less than 1
means a speed up and greater than 1 means a slowdown. Green lines
beginning with + are slowdowns (the PR is slower then master or
master is slower than the previous release). Red lines beginning
with - are speedups.

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Significantly changed benchmark results (master vs previous release)

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jksuom commented Oct 1, 2021

Looks good.

@jksuom jksuom merged commit 9ad1c20 into sympy:master Oct 1, 2021
@0sidharth 0sidharth deleted the issue_22181 branch November 23, 2021 14:47
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Simple limit crashes

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