petsc-3.3-p7 2013-05-11

MatMFFDDSSetUmin

 Sets the "umin" parameter used by the PETSc routine for computing the differencing parameter, h, which is used for matrix-free Jacobian-vector products.

Synopsis

#include "petscmat.h"   
PetscErrorCode  MatMFFDDSSetUmin(Mat A,PetscReal umin)

Input Parameters

A - the matrix created with MatCreateSNESMF()
umin - the parameter

Notes

See the manual page for MatCreateSNESMF() for a complete description of the algorithm used to compute h.

See Also

MatMFFDSetFunctionError(), MatCreateSNESMF()

Level:advanced
Location:src/mat/impls/mffd/mffddef.c
Index of all Mat routines
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Index of all manual pages