The form of the factorization depends on the properties of the matrix A . Diagonally dominant matrices themselves are examples of diagonally dominant-like matrices. Additional permutations are performed on the matrix for the sake of parallelism. Band matrices use the band storage scheme described in section 4.4.3 . While the primary use of a matrix factorization is to solve a system of equations, other related tasks are provided as well.
Iterative refinement is done in the same precision as the input data.
In particular, the residual is not computed with extra precision, as has been traditionally done.