ENH: decomposePar: added logic for preserving baffles

applications/utilities/parallelProcessing/decomposePar/decomposeParDict

@@ -33,6 +33,11 @@ numberOfSubdomains  2;
 //singleProcessorFaceSets ((f0 -1));
 
 
+//- Keep owner and neighbour of baffles on same processor (i.e. keep it
+//  detectable as a baffle). Baffles are two boundary face sharing the
+//  same points.
+//preserveBaffles true;
+
 //- Use the volScalarField named here as a weight for each cell in the
 //  decomposition.  For example, use a particle population field to decompose
 //  for a balanced number of particles in a lagrangian simulation.

src/mesh/autoMesh/autoHexMesh/meshRefinement/meshRefinement.C

@@ -1209,18 +1209,19 @@ Foam::autoPtr<Foam::mapDistributePolyMesh> Foam::meshRefinement::balance
         PtrList<labelList> specifiedProcessorFaces;
         labelList specifiedProcessor;
 
+        // Pairs of baffles
+        List<labelPair> couples;
+
         // Constraints from decomposeParDict
         decomposer.setConstraints
         (
             mesh_,
             blockedFace,
             specifiedProcessorFaces,
-            specifiedProcessor
+            specifiedProcessor,
+            couples
         );
 
-        // Pairs of baffles
-        List<labelPair> couples;
-
 
         if (keepZoneFaces || keepBaffles)
         {
@@ -1314,12 +1315,43 @@ Foam::autoPtr<Foam::mapDistributePolyMesh> Foam::meshRefinement::balance
 
             if (keepBaffles)
             {
-                // Get boundary baffles that need to stay together.
-                couples = getDuplicateFaces   // all baffles
-                (
-                    identity(mesh_.nFaces()-mesh_.nInternalFaces())
-                   +mesh_.nInternalFaces()
-                );
+                label nBnd = mesh_.nFaces()-mesh_.nInternalFaces();
+
+                labelList coupledFace(mesh_.nFaces(), -1);
+                {
+                    // Get boundary baffles that need to stay together
+                    List<labelPair> allCouples = getDuplicateFaces
+                    (
+                        identity(nBnd)
+                       +mesh_.nInternalFaces()
+                    );
+
+                    // Merge with any couples from
+                    // decompositionMethod::setConstraints
+                    forAll(couples, i)
+                    {
+                        const labelPair& baffle = couples[i];
+                        coupledFace[baffle.first()] = baffle.second();
+                        coupledFace[baffle.second()] = baffle.first();
+                    }
+                    forAll(allCouples, i)
+                    {
+                        const labelPair& baffle = allCouples[i];
+                        coupledFace[baffle.first()] = baffle.second();
+                        coupledFace[baffle.second()] = baffle.first();
+                    }
+                }
+
+                couples.setSize(nBnd);
+                label nCpl = 0;
+                forAll(coupledFace, faceI)
+                {
+                    if (coupledFace[faceI] != -1 && faceI < coupledFace[faceI])
+                    {
+                        couples[nCpl++] = labelPair(faceI, coupledFace[faceI]);
+                    }
+                }
+                couples.setSize(nCpl);
             }
             label nCouples = returnReduce(couples.size(), sumOp<label>());
 

src/parallel/decompose/decompositionMethods/Make/options

@@ -1,7 +1,9 @@
 EXE_INC = \
     -I$(LIB_SRC)/meshTools/lnInclude \
+    -I$(LIB_SRC)/dynamicMesh/lnInclude \
     -I$(LIB_SRC)/finiteVolume/lnInclude
 
 LIB_LIBS = \
     -lmeshTools \
+    -ldynamicMesh \
     -lfiniteVolume

src/parallel/decompose/decompositionMethods/decompositionMethod/decompositionMethod.C

@@ -32,6 +32,7 @@ InClass
 #include "Tuple2.H"
 #include "faceSet.H"
 #include "regionSplit.H"
+#include "localPointRegion.H"
 
 // * * * * * * * * * * * * * * Static Data Members * * * * * * * * * * * * * //
 
@@ -984,15 +985,16 @@ void Foam::decompositionMethod::setConstraints
     const polyMesh& mesh,
     boolList& blockedFace,
     PtrList<labelList>& specifiedProcessorFaces,
-    labelList& specifiedProcessor
+    labelList& specifiedProcessor,
+    List<labelPair>& explicitConnections
 )
 {
     blockedFace.setSize(mesh.nFaces());
     blockedFace = true;
-    label nUnblocked = 0;
+    //label nUnblocked = 0;
 
     specifiedProcessorFaces.clear();
-    specifiedProcessor.setSize(0);
+    explicitConnections.clear();
 
 
     if (decompositionDict_.found("preservePatches"))
@@ -1024,7 +1026,7 @@ void Foam::decompositionMethod::setConstraints
                 if (blockedFace[pp.start() + i])
                 {
                     blockedFace[pp.start() + i] = false;
-                    nUnblocked++;
+                    //nUnblocked++;
                 }
             }
         }
@@ -1058,20 +1060,103 @@ void Foam::decompositionMethod::setConstraints
                 if (blockedFace[fz[i]])
                 {
                     blockedFace[fz[i]] = false;
-                    nUnblocked++;
+                    //nUnblocked++;
                 }
             }
         }
     }
 
+    bool preserveBaffles = decompositionDict_.lookupOrDefault
+    (
+        "preserveBaffles",
+        false
+    );
+    if (preserveBaffles)
+    {
+        Info<< nl
+            << "Keeping owner of faces in baffles "
+            << " on same processor." << endl;
+
+        // Faces to test: all boundary faces
+        labelList testFaces
+        (
+            identity(mesh.nFaces()-mesh.nInternalFaces())
+          + mesh.nInternalFaces()
+        );
+
+        // Find correspondencing baffle face (or -1)
+        labelList duplicateFace
+        (
+            localPointRegion::findDuplicateFaces
+            (
+                mesh,
+                testFaces
+            )
+        );
+
+        const polyBoundaryMesh& patches = mesh.boundaryMesh();
+
+        // Convert into list of coupled face pairs (mesh face labels).
+        explicitConnections.setSize(testFaces.size());
+        label dupI = 0;
+
+        forAll(duplicateFace, i)
+        {
+            label otherFaceI = duplicateFace[i];
+
+            if (otherFaceI != -1 && i < otherFaceI)
+            {
+                label meshFace0 = testFaces[i];
+                label patch0 = patches.whichPatch(meshFace0);
+                label meshFace1 = testFaces[otherFaceI];
+                label patch1 = patches.whichPatch(meshFace1);
+
+                // Check for illegal topology. Should normally not happen!
+                if
+                (
+                    (patch0 != -1 && isA<processorPolyPatch>(patches[patch0]))
+                 || (patch1 != -1 && isA<processorPolyPatch>(patches[patch1]))
+                )
+                {
+                    FatalErrorIn
+                    (
+                        "decompositionMethod::decompose(const polyMesh&)"
+                    )   << "One of two duplicate faces is on"
+                        << " processorPolyPatch."
+                        << "This is not allowed." << nl
+                        << "Face:" << meshFace0
+                        << " is on patch:" << patches[patch0].name()
+                        << nl
+                        << "Face:" << meshFace1
+                        << " is on patch:" << patches[patch1].name()
+                        << abort(FatalError);
+                }
+
+                explicitConnections[dupI++] = labelPair(meshFace0, meshFace1);
+                if (blockedFace[meshFace0])
+                {
+                    blockedFace[meshFace0] = false;
+                    //nUnblocked++;
+                }
+                if (blockedFace[meshFace1])
+                {
+                    blockedFace[meshFace1] = false;
+                    //nUnblocked++;
+                }
+            }
+        }
+        explicitConnections.setSize(dupI);
+    }
+
     if
     (
         decompositionDict_.found("preservePatches")
      || decompositionDict_.found("preserveFaceZones")
+     || preserveBaffles
     )
     {
         syncTools::syncFaceList(mesh, blockedFace, andEqOp<bool>());
-        reduce(nUnblocked, sumOp<label>());
+        //reduce(nUnblocked, sumOp<label>());
     }
 
 
@@ -1303,12 +1388,14 @@ Foam::labelList Foam::decompositionMethod::decompose
     boolList blockedFace;
     PtrList<labelList> specifiedProcessorFaces;
     labelList specifiedProcessor;
+    List<labelPair> explicitConnections;
     setConstraints
     (
         mesh,
         blockedFace,
         specifiedProcessorFaces,
-        specifiedProcessor
+        specifiedProcessor,
+        explicitConnections
     );
 
 
@@ -1322,7 +1409,7 @@ Foam::labelList Foam::decompositionMethod::decompose
         blockedFace,            // any cells to be combined
         specifiedProcessorFaces,// any whole cluster of cells to be kept
         specifiedProcessor,
-        List<labelPair>()       // no baffles
+        explicitConnections     // baffles
     );
 
     return finalDecomp;

src/parallel/decompose/decompositionMethods/decompositionMethod/decompositionMethod.H

@@ -256,13 +256,19 @@ public:
             //);
 
 
-            //- Helper: extract constraints
+            //- Helper: extract constraints:
+            //  blockedface: existing faces where owner and neighbour on same
+            //               proc
+            //  explicitConnections: sets of boundary faces  ,,     ,,
+            //  specifiedProcessorFaces: groups of faces with all cells on
+            //  same processor.
             void setConstraints
             (
                 const polyMesh& mesh,
                 boolList& blockedFace,
                 PtrList<labelList>& specifiedProcessorFaces,
-                labelList& specifiedProcessor
+                labelList& specifiedProcessor,
+                List<labelPair>& explicitConnections
             );
 
             // Decompose a mesh with constraints: