On Wed, Apr 1, 2015 at 10:57 AM, Sahai, Amal <[email protected]> wrote:
> I've been trying to figure this out for some time now and I really don't
> understand whats going on. I have a system called RAD which has been
> inherited from System class. I am setting values at node points using the
> following function:
>
> void set_nodal_value(const Node *n, System& sys, unsigned int varnum, Real
> value)
> {
> const unsigned int dof_index = n->dof_number(sys.number(), varnum, 0);
> sys.solution->set(dof_index, value);
> }
>
Be careful doing this in parallel. If dof_index is not owned by the
current processor you probably don't want to call solution->set(). Also a
small point is that you should catch dof_index as a dof_id_type, not an
unsigned int.
>
> The code which calls this looks like:
>
> set_nodal_value(current_node, rad_system, r_distance_var, (*current_node -
> *first_node).size());
>
> const unsigned int dof_index =
> current_node->dof_number(rad_system.number(), r_distance_var, 0);
> std::cout<< dof_index <<"\t"<<(*rad_system.solution)(dof_index)<<"\n";
>
> Right after assigning some value to a certain dof_index, when I try
> outputting the value at the same dof index in the solution vector (in the
> 2nd and 3rd lines), this value turns out to be zero. But later when I use
> the write_equation_systems command to write out a solution value, the
> values that I had previously assigned are written out.
>
> Even after doing a system.solution->update, the solution vector seems to
> be comprised of only 0's.
>
> Why is this happening?
>
When using PETSc, solution->set() calls VecSetValues() but doesn't call
VecAssemblyBegin()/End().
As David said, calling close() on the vector triggers the call to
VecAssemblyBegin()/End()
System::update() updates the current_local_solution to reflect values in
the solution vector.
--
John
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