Call a method on a PETSc object, that is a function in the objects function table obj->ops, skip if the method does not exist
#include "petsc/private/petscimpl.h" PetscTryTtype(obj,method,other_args)
obj - the object the method is called on
method - the name of the method, for example, mult for the PETSc routine MatMult()
other_args - the other arguments for the method, obj is the first argument
This does not return an error code, it is a macro that returns with an error code on error.