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#
-mat_mffd_compute_normu - Compute the norm of u every time see
MatMFFDWPSetComputeNormU()
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#
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#
Index of all Mat routines
Table of Contents for all manual pages
Index of all manual pages