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Ignoring overlap cells in parallel ILU factorization (#1610)

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* fixed the issue of including ghost cells in preconditioning, by zeroing out ghost rows and setting the diagonal to a large value.

* move altering of matrix to a function

* blockwise modification of matrix

* add findOverlapRowsAndColumns in BlacoilDetail. Add call to findOverlapRowsAndColumns in constructor of BlacoilModelEbos. Change makeOverlapRowsInvalid, by looping over precalculated inddies instead of grid

* Better formatting
This commit is contained in:
andrthu 2018-11-06 14:14:50 +01:00 committed by Atgeirr Flø Rasmussen
parent 6c5b540eaf
commit a969fd198a
2 changed files with 88 additions and 4 deletions
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49
opm/autodiff/BlackoilDetails.hpp
View File

@ -196,7 +196,56 @@ namespace detail {
return grid.comm().sum(count);
}
/// \brief Find the rows corresponding to overlap cells
///
/// Loop over grid and store cell ids of row-column pairs
/// corresponding to overlap cells.
/// \tparam The type of the DUNE grid.
/// \param grid The grid where we look for overlap cells.
/// \param overlapRowAndColumns List where overlap rows and columns are stored.
template<class Grid>
void findOverlapRowsAndColumns(const Grid& grid, std::vector<std::pair<int,std::vector<int>>>& overlapRowAndColumns )
{
//only relevant in parallel case.
if ( grid.comm().size() > 1)
{
//Numbering of cells
auto lid = grid.localIdSet();
const auto& gridView = grid.leafGridView();
auto elemIt = gridView.template begin<0>();
const auto& elemEndIt = gridView.template end<0>();
//loop over cells in mesh
for (; elemIt != elemEndIt; ++elemIt)
{
const auto& elem = *elemIt;
//If cell has partition type not equal to interior save row
if (elem.partitionType() != Dune::InteriorEntity)
{
//local id of overlap cell
int lcell = lid.id(elem);
std::vector<int> columns;
//loop over faces of cell
auto isend = gridView.iend(elem);
for (auto is = gridView.ibegin(elem); is!=isend; ++is)
{
//check if face has neighbor
if (is->neighbor())
{
//get index of neighbor cell
int ncell = lid.id(is->outside());
columns.push_back(ncell);
}
}
//add row to list
overlapRowAndColumns.push_back(std::pair<int,std::vector<int>>(lcell,columns));
}
}
}
}
} // namespace detail
} // namespace Opm

43
opm/autodiff/BlackoilModelEbos.hpp
View File

@ -166,6 +166,8 @@ namespace Opm {
{
// compute global sum of number of cells
global_nc_ = detail::countGlobalCells(grid_);
//find rows of matrix corresponding to overlap
detail::findOverlapRowsAndColumns(grid_,overlapRowAndColumns_);
if (!istlSolver_)
{
OPM_THROW(std::logic_error,"solver down cast to ISTLSolver failed");
@ -472,6 +474,32 @@ namespace Opm {
return istlSolver().iterations();
}
/// Zero out off-diagonal blocks on rows corresponding to overlap cells
/// Diagonal blocks on ovelap rows are set to diag(1e100).
void makeOverlapRowsInvalid(Mat& ebosJacIgnoreOverlap) const
{
//value to set on diagonal
MatrixBlockType diag_block(0.0);
for (int eq = 0; eq < numEq; ++eq)
diag_block[eq][eq] = 1.0e100;
//loop over precalculated overlap rows and columns
for (auto row = overlapRowAndColumns_.begin(); row != overlapRowAndColumns_.end(); row++ )
{
int lcell = row->first;
//diagonal block set to large value diagonal
ebosJacIgnoreOverlap[lcell][lcell] = diag_block;
//loop over off diagonal blocks in overlap row
for (auto col = row->second.begin(); col != row->second.end(); ++col)
{
int ncell = *col;
//zero out block
ebosJacIgnoreOverlap[lcell][ncell] = 0.0;
}
}
}
/// Solve the Jacobian system Jx = r where J is the Jacobian and
/// r is the residual.
void solveJacobianSystem(BVector& x) const
@ -497,9 +525,16 @@ namespace Opm {
const Mat& actual_mat_for_prec = matrix_for_preconditioner_ ? *matrix_for_preconditioner_.get() : ebosJac;
// Solve system.
if( isParallel() )
{
{
typedef WellModelMatrixAdapter< Mat, BVector, BVector, BlackoilWellModel<TypeTag>, true > Operator;
Operator opA(ebosJac, actual_mat_for_prec, wellModel(),
auto ebosJacIgnoreOverlap = Mat(ebosJac);
//remove ghost rows in local matrix
makeOverlapRowsInvalid(ebosJacIgnoreOverlap);
//Not sure what actual_mat_for_prec is, so put ebosJacIgnoreOverlap as both variables
//to be certain that correct matrix is used for preconditioning.
Operator opA(ebosJacIgnoreOverlap, ebosJacIgnoreOverlap, wellModel(),
istlSolver().parallelInformation() );
assert( opA.comm() );
istlSolver().solve( opA, x, ebosResid, *(opA.comm()) );
@ -956,8 +991,8 @@ namespace Opm {
double current_relaxation_;
BVector dx_old_;
std::unique_ptr<Mat> matrix_for_preconditioner_;
std::unique_ptr<Mat> matrix_for_preconditioner_;
std::vector<std::pair<int,std::vector<int>>> overlapRowAndColumns_;
public:
/// return the StandardWells object
BlackoilWellModel<TypeTag>&