ENH: Allow a weightField volScalarField to be specified in decomposeParDict.

Weights the cells in the decomposition.

applications/utilities/parallelProcessing/decomposePar/decomposeParDict

@@ -19,15 +19,17 @@ FoamFile
 
 numberOfSubdomains  8;
 
-
 //- Keep owner and neighbour on same processor for faces in zones:
 // preserveFaceZones (heater solid1 solid3);
 
-
 //- Keep owner and neighbour on same processor for faces in patches:
 //  (makes sense only for cyclic patches)
 //preservePatches (cyclic_half0 cyclic_half1);
 
+//- 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.
+// weightField dsmcRhoNMean;
 
 method          scotch;
 // method          hierarchical;
@@ -59,11 +61,8 @@ multiLevelCoeffs
     }
 }
 
-
 // Desired output
 
-
-
 simpleCoeffs
 {
     n           (2 1 1);

applications/utilities/parallelProcessing/decomposePar/domainDecomposition.C

@@ -24,7 +24,6 @@ License
 \*---------------------------------------------------------------------------*/
 
 #include "domainDecomposition.H"
-#include "Time.H"
 #include "dictionary.H"
 #include "labelIOList.H"
 #include "processorPolyPatch.H"

applications/utilities/parallelProcessing/decomposePar/domainDecomposition.H

@@ -41,6 +41,9 @@ SourceFiles
 #include "SLList.H"
 #include "PtrList.H"
 #include "point.H"
+#include "Time.H"
+#include "volFields.H"
+
 
 namespace Foam
 {

applications/utilities/parallelProcessing/decomposePar/domainDecompositionDistribute.C

@@ -113,9 +113,37 @@ void Foam::domainDecomposition::distributeCells()
     );
 
     if (sameProcFaces.empty())
+    {
+        if (decompositionDict_.found("weightField"))
+        {
+            word weightName = decompositionDict_.lookup("weightField");
+
+            volScalarField weights
+            (
+                IOobject
+                (
+                    weightName,
+                    time().timeName(),
+                    *this,
+                    IOobject::MUST_READ,
+                    IOobject::NO_WRITE
+                ),
+                *this
+            );
+
+            cellToProc_ = decomposePtr().decompose
+            (
+                *this,
+                cellCentres(),
+                weights.internalField()
+            );
+        }
+        else
         {
             cellToProc_ = decomposePtr().decompose(*this, cellCentres());
         }
+
+    }
     else
     {
         Info<< "Selected " << sameProcFaces.size()
@@ -173,6 +201,42 @@ void Foam::domainDecomposition::distributeCells()
 
         // Do decomposition on agglomeration
         // ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+        if (decompositionDict_.found("weightField"))
+        {
+            scalarField regionWeights(globalRegion.nRegions(), 0);
+
+            word weightName = decompositionDict_.lookup("weightField");
+
+            volScalarField weights
+            (
+                IOobject
+                (
+                    weightName,
+                    time().timeName(),
+                    *this,
+                    IOobject::MUST_READ,
+                    IOobject::NO_WRITE
+                ),
+                *this
+            );
+
+            forAll(globalRegion, cellI)
+            {
+                label regionI = globalRegion[cellI];
+
+                regionWeights[regionI] += weights.internalField()[cellI];
+            }
+
+            cellToProc_ = decomposePtr().decompose
+            (
+                *this,
+                globalRegion,
+                regionCentres,
+                regionWeights
+            );
+        }
+        else
+        {
             cellToProc_ = decomposePtr().decompose
             (
                 *this,
@@ -180,6 +244,7 @@ void Foam::domainDecomposition::distributeCells()
                 regionCentres
             );
         }
+    }
 
     Info<< "\nFinished decomposition in "
         << decompositionTime.elapsedCpuTime()