Prevent segfault on GF(2^e) dense matrix row/column swap #40291
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where is this check currently performed? I think it would simplify the code to remove the check at that place. also I think it's a good idea to add |
I might be mistaken, but I read the initial comment as "these checks are within M4RI" (or M4RIE maybe?). In which case it may be worth raising the issue at the relevant repository. |
There is currently a problem with n x 0 and 0 x n matrices over GF(2^e). When performing row or column swaps, a segmentation fault is produced. The underlying issue seems to be within the M4RI library. Although the existing library code already has checks for these, they seem to be failing. A simple example to reproduce the problem is:
sage: matrix.zero(GF(4),2,0).with_permuted_rows(Permutation([2,1]))
The issue may be avoided in Sage by only performing swaps on non-empty rows and columns. I have added a simple condition to the swap logic for matrix_gf2e_dense
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