Both ILU0 and ILUT preconditioners can apply to any non-degenerate matrix.
They can be used alone or together with the
Intel® oneAPI Math Kernel
RCI FGMRES solver (seeSparse Solver Routines
). Avoid using these preconditioners with MKL RCI
CG solver because in general, they produce a non-symmetric resulting matrix even if the
original matrix is symmetric. Usually, an inverse of the preconditioner is required in this
case. To do this the
Intel® oneAPI Math Kernel Library
must be applied twice: for the lower triangular part
of the preconditioner, and then for its upper triangular part.