DUNE PDELab (git)
Helper class for adding up matrix entries on border. More...
#include <dune/pdelab/gridoperator/common/borderdofexchanger.hh>
Classes | |
class | EntryAccumulator |
A DataHandle class to exchange matrix entries. More... | |
class | PatternExtender |
A DataHandle class to exchange matrix sparsity patterns. More... | |
Public Member Functions | |
NonOverlappingBorderDOFExchanger (const GridOperator &grid_operator) | |
Constructor. Sets up the local to global relations. More... | |
void | accumulateBorderEntries (const GridOperator &grid_operator, Matrix &matrix) |
Sums up the entries corresponding to border vertices. More... | |
Detailed Description
class Dune::PDELab::NonOverlappingBorderDOFExchanger< GridOperator >
Helper class for adding up matrix entries on border.
Utility class for accumulating matrix entries for border-border couplings in parallel computations with nonoverlapping domain decomposition.
For nonoverlapping grids, there is an additional problem related to matrix entries that should exist on a given node, but which are only present on a remote node. For these entries, we not only need to accumulate the matrix values, we also have to create those matrix entries in the sparsity pattern, as they cannot be discovered during the node-local matrix creation:
We look at a 2D example with a nonoverlapping grid, two processes and no ghosts with Q1 discretization. Process 0 has the left part of the domain with three cells and eight vertices (1-8), Process 1 the right part with three cells and eight vertices (2,4,7-12).
1 _ 2 2 _ 9 _ 10 | | | | | 3 _ 4 _ 7 4 _ 7 _ 11 | | | | | 5 _ 6 _ 8 8 _ 12
If we look at vertex 7 and the corresponding entries in the matrix for P0, there will be entries for (7,4) and (7,8), but not for (7,2). Unfortunately, local pattern creation will not create the link (7,2) on process 0. This class will find this kind of entry and extend the sparsity pattern appropriately.
- Template Parameters
-
GridOperator The grid operator to work on.
The documentation for this class was generated from the following file:
- dune/pdelab/gridoperator/common/borderdofexchanger.hh