[petsc-users] How to efficiently assemble this matrix?

[Jed Brown]

Italo Tasso <bichinhoverde at spwinternet.com.br> writes:

> I have two matrices: matrix A is 4n x 4n and matrix C is n x n. I want to
> set the values of A using the values of C, like this:
>
> A[4i+k][4j+k] = C[i][j]
> 0 < i < n
> 0 < j < n
> 0 < k < 3

MatCreateMAIJ(C,4,&A)

will create this linear operator in O(1) time and space (just
referencing C).  Is that what you want?
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