#335 big matrix crash (symm but not posdef)

[Sven Schreiber]

int-32 overflow in a rather special case (symm matrix, but not pos def, and very big);
this line in real_invert_symmetric_matrix seems to overflow :

int bytes = n * n * sizeof *aval; ``

[Allin Cottrell]

The line referenced above should be size_t bytes = n * n * sizeof *aval; and it's now corrected in git.

A note on M = upper(M) + upper(M)' : given that M is 23171 x 23171, this line calls for more than 12GB of storage., and so is likely to bring some computers to their knees.

[Sven Schreiber]

Am 05.09.2026 um 14:51 schrieb Allin Cottrell:

The line referenced above should be size_t bytes = n * n * sizeof *aval; and it's now corrected in git.

A note on M = upper(M) + upper(M)' : given that M is 23171 x 23171, this line calls for more than 12GB of storage., and so is likely to bring some computers to their knees.

Right - this was just a quick proof, not a refined test script. I'm not
used to having symmetric-but-indefinite matrices in my scripts.

thanks, sven