Name

gf_precond — Create a preconditioner

Calling Sequence

gf_precond('identity')
gf_precond('cidentity')
gf_precond('diagonal', vec D)
gf_precond('ildlt', spmat M)
gf_precond('ilu', spmat M)
gf_precond('ildltt', spmat M [, int fillin [, scalar threshold]])
gf_precond('ilut', spmat M [, int fillin [, scalar threshold]])gf_precond('superlu', spmat M)
    

Description

The preconditioners may store REAL or COMPLEX values. They accept getfem sparse matrices and Scilab sparse matrices.

  • gf_precond('identity') Create a REAL identity precondioner.

  • gf_precond('cidentity') Create a COMPLEX identity preconditioner.

  • gf_precond('diagonal', vec D) Create a diagonal precondioner.

  • gf_precond('ildlt', Spmat m) Create an ILDLT (Cholesky) preconditioner for the (symmetric) sparse matrix `m`. This preconditioner has the same sparsity pattern than `m` (no fill-in).

  • gf_precond('ilu', Spmat m) Create an ILU (Incomplete LU) preconditioner for the sparse matrix `m`. This preconditioner has the same sparsity pattern than `m` (no fill-in).

  • gf_precond('ildltt', Spmat m[, int fillin[, scalar threshold]]) Create an ILDLT (Cholesky with filling) preconditioner for the (symmetric) sparse matrix `m`. The preconditioner may add at most `fillin` additional non-zero entries on each line. The default value for `fillin` is 10, and the default threshold is1e-7.

  • gf_precond('ilut', Spmat m[, int fillin[, scalar threshold]]) Create an ILUT (Incomplete LU with filling) preconditioner for the sparse matrix `m`. The preconditioner may add at most `fillin` additional non-zero entries on each line. The default value for `fillin` is 10, and the default threshold is 1e-7.

  • gf_precond('superlu', Spmat m) Uses SuperLU to build an exact factorization of the sparse matrix `m`. This preconditioner is only available if the getfem-interface was built with SuperLU support

    Note that LU factorization is likely to eat all your memory for 3D problems.

See Also

gf_precond_get, gf_linsolve

Authors

Y. Collette