Fix bug in gr_mat_move_row#2511
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fredrik-johansson merged 2 commits intoflintlib:mainfrom Dec 3, 2025
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…reduced, both affecting LLL for rank-deficient matrices
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I think the original code was never intended for the rank-deficient case. See #1168. |
lgoettgens
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Dec 2, 2025
| /* Failure with the fmpq context implied that we attempted to divide | ||
| by an exactly zero GS norm; by the current definition, this | ||
| matrix is not reduced. */ | ||
| if (prec >= exact_cutoff) |
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This second if statement will never evaluate to true, as the condition is already checked in the previous one. Is this intended?
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The statement was indeed duplicated; thanks for spotting.
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I can verify that with this patch applied, the errors from thofma/Hecke.jl#2095 disappear. |
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Hopefully fixes #2510.
Also fixes
fmpz_mat_is_reducedto not hang when checking the output. BTW,fmpz_mat_is_reducedreturns false in flint-3.3 here, and I've made it return the same thing. Was this the intended behavior?Unfortunately our test code for
fmpz_lllseems to do a really poor job testing rank-deficient matrices.