#include "petscsnes.h" PetscErrorCode SNESDefaultMatrixFreeSetParameters2(Mat mat,PetscReal error,PetscReal umin,PetscReal h)
      J(u)*a = [J(u+h*a) - J(u)]/h where
either the user sets h directly here, or this parameter is computed via
       h = error_rel*u'a/||a||^2                        if  |u'a| > umin*||a||_{1}
         = error_rel*umin*sign(u'a)*||a||_{1}/||a||^2   else
| mat | - the matrix | |
| error_rel | - relative error (should be set to the square root of the relative error in the function evaluations) | |
| umin | - minimum allowable u-value | |
| h | - differencing parameter | 
Level:advanced
Location:src/snes/interface/noise/snesmfj2.c
Index of all SNES routines
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Index of all manual pages