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Robustness improvement on top block AMG level

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This commit is contained in:
Hrvoje Jasak 2018-05-25 10:23:32 +01:00
parent f00636e865
commit facf4bc864
1 changed files with 19 additions and 6 deletions
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25
src/foam/matrices/blockLduMatrix/BlockAMG/coarseBlockAMGLevel.C
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@ -212,13 +212,11 @@ void Foam::coarseBlockAMGLevel<Type>::solve
"topLevelCorr" "topLevelCorr"
); );
label maxIter = Foam::min(2*coarseningPtr_->minCoarseEqns(), 100);
// Create artificial dictionary for top-level solution // Create artificial dictionary for top-level solution
dictionary topLevelDict; dictionary topLevelDict;
topLevelDict.add("nDirections", "5"); topLevelDict.add("nDirections", "5");
topLevelDict.add("minIter", 1); topLevelDict.add("minIter", 1);
topLevelDict.add("maxIter", maxIter); topLevelDict.add("maxIter", 500);
topLevelDict.add("tolerance", tolerance); topLevelDict.add("tolerance", tolerance);
topLevelDict.add("relTol", relTol); topLevelDict.add("relTol", relTol);
@ -245,8 +243,8 @@ void Foam::coarseBlockAMGLevel<Type>::solve
if (matrixPtr_->symmetric()) if (matrixPtr_->symmetric())
{ {
// Note: top-level preconditioner is incorrect: FIX. HJ, 3/Oct/2017 // Note: must change preconditioner to C0. HJ. 10/Oct/2017
topLevelDict.add("preconditioner", "Cholesky"); topLevelDict.add("preconditioner", "ILUC0");
coarseSolverPerf = BlockCGSolver<Type> coarseSolverPerf = BlockCGSolver<Type>
( (
@ -268,10 +266,25 @@ void Foam::coarseBlockAMGLevel<Type>::solve
).solve(x, b); ).solve(x, b);
} }
// Check for convergence
const scalar magInitialRes = mag(coarseSolverPerf.initialResidual());
const scalar magFinalRes = mag(coarseSolverPerf.finalResidual());
if (magFinalRes > magInitialRes && magInitialRes > SMALL)
{
if (blockLduMatrix::debug)
{
Info<< "Divergence in top AMG level" << endl;
coarseSolverPerf.print();
}
x = pTraits<Type>::zero;
}
// Restore debug // Restore debug
blockLduMatrix::debug = oldDebug; blockLduMatrix::debug = oldDebug;
if (blockLduMatrix::debug >= 3) if (blockLduMatrix::debug >= 2)
{ {
coarseSolverPerf.print(); coarseSolverPerf.print();
} }