PetscOptionsSetValue

Sets an option name-value pair in the options database, overriding whatever is already present.

#include "petsc.h"   
int PetscOptionsSetValue(const char iname[],const char value[])

Not collective, but setting values on certain processors could cause problems for parallel objects looking for options.

	name	- name of option, this SHOULD have the - prepended
	value	- the option value (not used for all options)

Only some options have values associated with them, such as -ksp_rtol tol. Other options stand alone, such as -ksp_monitor.