I have a matrix
A = [A11 A12;A21 A22];
and I'd like to compute the Schur complement of A11 in A using pardiso: S = A22 - A21 * A11^-1 * A12. This seems well supported by the PARDISO-SCHUR routine IPARM(38).
S = A22 - A21 * A11^-1 * A12
However, I'm wondering if I can do some prefactorization on A11 so that if I change only A12,A21,A22 then I could compute S quickly (quicker than just recomputing everything).
Is there an interface to alter part of A?
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