Hi IIiya,

On Thursday, February 22, 2018 at 11:55:33 AM UTC+1, Bryukhanov Ilya wrote:
> Denis, thanks a lot for the answer!
> I think that on the first step I can use usual 
> "interpolate_boundary_values + apply_boundary_values" functions,

the outline I gave above is agnostic to "first step"/"other steps", you 
would call VectorTools::interpolate_boundary_values() regardless 
stage to get constraints into the ConstraintMatrix object. If you do 
Newton-Raphson and solve for increments, at the first non-linear step you 
should have all constraints (hanging nodes + non-zero Dirichlet for a given 
step in quasi-static(?) loading), and for consequent steps only hanging 
nodes plus zero Dirichlet. 

Please read this module:

This code-gallery may help in figuring out how to do 


> that transform the global matrix: columns of the constrained nodes become 
> zero columns with diagonal non-zero entries.
> In a time loop I have to account boundary condition without modifing 
> global matrix. While looping over dirichlet constrained cells
> I call the function  
> "hanging_node_constraints.distribute_local_to_global(cell_rhs, 
> local_dof_indices, system_rhs, cell_matrix)"
> which modifies the system_rhs vector by adding columns from constrained 
> nodes, which are actually zero in global matrix.
Nope, if your "hanging_node_constraints" indeed contains only constraints 
from hanging nodes, you won't see any contribution to the RHS
from it as constraints are homogeneous (ie. you wont' have  u_{123} = 456 
from hanging nodes).

> Also I need to add components to rhs vector from the force boundary 
> conditions.

that's a different story, just do integration over faces and distribute as 

> However, I have to somehow account Dirichlet boundary conditions as in 
> previous step I didn't use any boundary values. The function

use ConstraintMatrix which has non-zero Dirichlet BC constraints.

> "interpolate_boundary_values(dof_handler, boundary_id, DirichletHandler, 
> boundary_values)"
> gives me "boundary_values" variables that maps node numbers to dirichle 
> boundary. 
> But I don't know how should I use it. What should I do with that variable 
> to account boundary conditions together with "distribute_local_to_global"?
> Thanks a lot in advance. Sorry for my misunderstanding.


The deal.II project is located at http://www.dealii.org/
For mailing list/forum options, see 
You received this message because you are subscribed to the Google Groups 
"deal.II User Group" group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to dealii+unsubscr...@googlegroups.com.
For more options, visit https://groups.google.com/d/optout.

Reply via email to