[petsc-users] How to manually set the matrix-free differencing parameter h?

[Ping He]

Hi,

I am using PETSc-SNES matrix free approach, and I would like to know how 
to manually set the differencing parameter h. I tried to use the 
SNESDefaultMatrixFreeSetParameters2 function but I got an error when 
compiling: ‘SNESDefaultMatrixFreeSetParameters2’ was not declared in 
this scope.

Thanks very much in advance.

Regards,
Ping