Opened 5 years ago

Closed 5 years ago

## #24450 closed enhancement (fixed)

# BruhatTitsTree.lift: bail out if matrix is not invertible

Reported by: | Jeroen Demeyer | Owned by: | |
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Priority: | major | Milestone: | sage-8.2 |

Component: | modular forms | Keywords: | |

Cc: | Marc Masdeu, David Roe | Merged in: | |

Authors: | Jeroen Demeyer | Reviewers: | David Roe |

Report Upstream: | N/A | Work issues: | |

Branch: | d61f9ea (Commits, GitHub, GitLab) | Commit: | d61f9ea30608521b19f1960cfeba9ace61adb51f |

Dependencies: | Stopgaps: |

### Description

If the determinant of the matrix is zero, the code does some very dubious things which happen to fail in the right way mostly by accident. This happens to break #24247, but it's clear that checking for a zero determinant makes sense anyway.

### Change History (4)

### comment:1 Changed 5 years ago by

Branch: | → u/jdemeyer/ticket/24450 |
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### comment:2 Changed 5 years ago by

Commit: | → d61f9ea30608521b19f1960cfeba9ace61adb51f |
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Status: | new → needs_review |

### comment:3 Changed 5 years ago by

Reviewers: | → David Roe |
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Status: | needs_review → positive_review |

Looks good to me.

### comment:4 Changed 5 years ago by

Branch: | u/jdemeyer/ticket/24450 → d61f9ea30608521b19f1960cfeba9ace61adb51f |
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Resolution: | → fixed |

Status: | positive_review → closed |

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New commits:

`BruhatTitsTree.lift: bail out if matrix is not invertible`