Dear FreeFEM users,

If I create two marices from my variation forms, say matrix A and B, can I do the operation A+B or A*B?

Actually, I have tried and it seems I was allowed to do so. However, I am not sure whether it was right or wrong?

I am curious how FreeFEM implement this, because matrix A and B are sparse matrices, which have different structures. Is this marices plus and multiplication operation very slow?

Another question: can I foce B have the same non-zero element structure as A?

Best,

Yongxing.