CircuitsMatroid: check for empty dict before min#41254
Merged
vbraun merged 1 commit intosagemath:developfrom Dec 21, 2025
Merged
CircuitsMatroid: check for empty dict before min#41254vbraun merged 1 commit intosagemath:developfrom
CircuitsMatroid: check for empty dict before min#41254vbraun merged 1 commit intosagemath:developfrom
Conversation
This was already working as intented (confusingly), probably due to some Cython optimization which avoided the min on an empty dict. I added the check for clarity and robustness. For example, this calls min on an empty dict: ```python sage: from sage.matroids.circuits_matroid import CircuitsMatroid sage: M = matroids.Uniform(5, 5) sage: CM = CircuitsMatroid(M) sage: CM.dependent_sets(2) SetSystem of 0 sets over 5 elements ``` The addition of a `print(min(self._k_C))` makes the issue clear, as it raises: ``` ValueError: min() iterable argument is empty ```
vbraun
pushed a commit
to vbraun/sage
that referenced
this pull request
Dec 20, 2025
sagemathgh-41254: `CircuitsMatroid`: check for empty dict before min This was already working as intented (confusingly), probably due to some Cython optimization which avoided the min on an empty dict. I added the check for clarity and robustness. For example, this calls min on an empty dict: ```python sage: from sage.matroids.circuits_matroid import CircuitsMatroid sage: M = matroids.Uniform(5, 5) sage: CM = CircuitsMatroid(M) sage: CM.dependent_sets(2) SetSystem of 0 sets over 5 elements ``` The addition of a `print(min(self._k_C))` makes the issue clear, as it raises: ``` ValueError: min() iterable argument is empty ``` URL: sagemath#41254 Reported by: gmou3 Reviewer(s): Travis Scrimshaw
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
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
3 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.
This was already working as intented (confusingly), probably due to some Cython optimization which avoided the min on an empty dict. I added the check for clarity and robustness.
For example, this calls min on an empty dict:
The addition of a
print(min(self._k_C))makes the issue clear, as it raises: