bpo-44698: Restore complex pow behaviour for small integral exponents #27772
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
mdickinson
commented
Aug 15, 2021
| { | ||
| Py_complex cn; | ||
|
|
||
| if (n > 100 || n < -100) { |
Member
Author
There was a problem hiding this comment.
This branch is now redundant: the bounds check is performed in the code that calls c_powi.
mdickinson
commented
Aug 15, 2021
mdickinson
added
needs backport to 3.9
needs backport to 3.10
gpshead
reviewed
Aug 15, 2021
mdickinson
commented
Aug 16, 2021
gpshead
approved these changes
Aug 16, 2021
Contributor
|
Thanks @mdickinson for the PR 🌮🎉.. I'm working now to backport this PR to: 3.9, 3.10. |
|
GH-27796 is a backport of this pull request to the 3.10 branch. |
|
GH-27797 is a backport of this pull request to the 3.9 branch. |
Member
Author
|
@gpshead Thank you for the review! |
miss-islington
pushed a commit
to miss-islington/cpython
that referenced
this pull request
Aug 17, 2021
…pythonGH-27772) (cherry picked from commit 4b9a2dc) Co-authored-by: Mark Dickinson <mdickinson@enthought.com>
miss-islington
pushed a commit
to miss-islington/cpython
that referenced
this pull request
Aug 17, 2021
…pythonGH-27772) (cherry picked from commit 4b9a2dc) Co-authored-by: Mark Dickinson <mdickinson@enthought.com>
mdickinson
added a commit
that referenced
this pull request
Aug 17, 2021
mdickinson
added a commit
that referenced
this pull request
Aug 17, 2021
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
5 participants
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
PR #27278 fixed undefined behaviour in complex exponentiation, but also changed the behaviour for exponentiations whose exponent was a small integer but not actually an
int, for example as in(3+4j)**2.0. In particular, the overflow behaviour for these expressions changed:Prior to #27278:
After #27278 :
This PR restores the old behaviour, but does not re-introduce the undefined behaviour fixed by the original PR.
https://bugs.python.org/issue44698