MatMFFDWPSetComputeNormU

Sets whether it computes the ||U|| used by the Walker-Pernice [PW98] PETSc routine for computing h. With any Krylov solver this need only be computed during the first iteration and kept for later.

Synopsis

#include "petscmat.h"   
PetscErrorCode MatMFFDWPSetComputeNormU(Mat A, PetscBool flag)

Input Parameters

• A - the MATMFFD matrix

• flag - PETSC_TRUE causes it to compute \(||U||\), PETSC_FALSE uses the previous value

Options Database Key

• -mat_mffd_compute_normu <true,false> - true by default, false can save calculations but you must be sure that \(||U||\) has not changed in the mean time.

Note

See the manual page for MATMFFD_WP for a complete description of the algorithm used to compute h.

References

[PW98]

M. Pernice and H. F. Walker. NITSOL: a Newton iterative solver for nonlinear systems. SIAM J. Sci. Stat. Comput., 19:302–318, 1998.

See Also

MATMFFD_WP, MATMFFD, MatMFFDSetFunctionError(), MatCreateSNESMF()

Level

advanced

Location

src/mat/impls/mffd/wp.c

Implementations

MatMFFDWPSetComputeNormU_P() in src/mat/impls/mffd/wp.c

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