MATMFFD_WP#

Implements an approach for computing the differencing parameter h used with the finite difference based matrix-free Jacobian. From Walker-Pernice [PW98] $\( h = error_rel * sqrt(1 + ||u||) / ||a|| \)$

Options Database Key#

Notes#

\( || U || \) does not change between linear iterations so is reused

In KSPGMRES \( || a || == 1 \) and so does not need to ever be computed except at restart when it is recomputed. Thus requires no global collectives when used with KSPGMRES

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, MATMFFD_DS, MatCreateMFFD(), MatCreateSNESMF(), MATMFFD_DS

Level#

intermediate

Location#

src/mat/impls/mffd/wp.c


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