Qin Lu <[email protected]> writes: > Hello, > > Is the RCM reordering available for ILU preconditioner in PETSc? The manual > says RCM works with LU factorization, but it does not mention it for > preconditioners.
It works for all factorization preconditioners (ILU, ICC, LU, Cholesky).
~/petsc/src/ksp/ksp/examples/tutorials$ ./ex2 -m 100 -n 100 -ksp_view -pc_type
ilu -pc_factor_mat_ordering_type rcm
KSP Object: 1 MPI processes
type: gmres
GMRES: restart=30, using Classical (unmodified) Gram-Schmidt
Orthogonalization with no iterative refinement
GMRES: happy breakdown tolerance 1e-30
maximum iterations=10000, initial guess is zero
tolerances: relative=9.80296e-07, absolute=1e-50, divergence=10000
left preconditioning
using PRECONDITIONED norm type for convergence test
PC Object: 1 MPI processes
type: ilu
ILU: out-of-place factorization
0 levels of fill
tolerance for zero pivot 2.22045e-14
using diagonal shift on blocks to prevent zero pivot [INBLOCKS]
matrix ordering: rcm
factor fill ratio given 1, needed 1
Factored matrix follows:
Mat Object: 1 MPI processes
type: seqaij
rows=10000, cols=10000
package used to perform factorization: petsc
total: nonzeros=49600, allocated nonzeros=49600
total number of mallocs used during MatSetValues calls =0
not using I-node routines
linear system matrix = precond matrix:
Mat Object: 1 MPI processes
type: seqaij
rows=10000, cols=10000
total: nonzeros=49600, allocated nonzeros=50000
total number of mallocs used during MatSetValues calls =0
not using I-node routines
Norm of error 0.00314611 iterations 84
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