lagrangian: Support meshToMesh mapping

Lagrangian is now compatible with the meshToMesh topology changer. If a
cloud is being simulated and this topology changer is active, then the
cloud data will be automatically mapped between the specified sequence
of meshes in the same way as the finite volume data. This works both for
serial and parallel simulations.

In addition, mapFieldsPar now also supports mapping of Lagrangian data
when run in parallel.

applications/utilities/preProcessing/mapFieldsPar/mapFieldsPar.C

@@ -31,11 +31,84 @@ Description
 \*---------------------------------------------------------------------------*/
 
 #include "argList.H"
-#include "mapMeshes.H"
+#include "fvMeshToFvMesh.H"
+#include "mapGeometricFields.H"
+#include "mapClouds.H"
 #include "cellVolumeWeightMethod.H"
 
 using namespace Foam;
 
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+void mapConsistentMesh
+(
+    const fvMesh& srcMesh,
+    const fvMesh& tgtMesh,
+    const word& mapMethod,
+    const HashSet<word>& selectedFields,
+    const bool noLagrangian
+)
+{
+    Info<< nl << "Consistently creating and mapping fields for time "
+        << srcMesh.time().timeName() << nl << endl;
+
+    fvMeshToFvMesh interp(srcMesh, tgtMesh, mapMethod);
+
+    Info<< nl << "Mapping geometric fields" << endl;
+
+    mapGeometricFields
+    (
+        interp,
+        selectedFields,
+        noLagrangian
+    );
+
+    if (!noLagrangian)
+    {
+        mapClouds(interp);
+    }
+}
+
+
+void mapSubMesh
+(
+    const fvMesh& srcMesh,
+    const fvMesh& tgtMesh,
+    const HashTable<word>& patchMap,
+    const wordList& cuttingPatches,
+    const word& mapMethod,
+    const HashSet<word>& selectedFields,
+    const bool noLagrangian
+)
+{
+    Info<< nl << "Creating and mapping fields for time "
+        << srcMesh.time().timeName() << nl << endl;
+
+    fvMeshToFvMesh interp
+    (
+        srcMesh,
+        tgtMesh,
+        mapMethod,
+        patchMap,
+        cuttingPatches
+    );
+
+    Info<< nl << "Mapping geometric fields" << endl;
+
+    mapGeometricFields
+    (
+        interp,
+        selectedFields,
+        noLagrangian
+    );
+
+    if (!noLagrangian)
+    {
+        mapClouds(interp);
+    }
+}
+
+
 // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
 int main(int argc, char *argv[])
@@ -162,7 +235,7 @@ int main(int argc, char *argv[])
 
     Info<< "\nCreate meshes\n" << endl;
 
-    fvMesh meshSource
+    fvMesh srcMesh
     (
         IOobject
         (
@@ -173,7 +246,7 @@ int main(int argc, char *argv[])
         false
     );
 
-    fvMesh meshTarget
+    fvMesh tgtMesh
     (
         IOobject
         (
@@ -184,15 +257,18 @@ int main(int argc, char *argv[])
         false
     );
 
-    Info<< "Source mesh size: " << meshSource.nCells() << tab
-        << "Target mesh size: " << meshTarget.nCells() << nl << endl;
+    Info<< "Source mesh size: "
+        << returnReduce(srcMesh.nCells(), sumOp<label>())
+        << ", Target mesh size: "
+        << returnReduce(tgtMesh.nCells(), sumOp<label>())
+        << endl;
 
     if (consistent)
     {
         mapConsistentMesh
         (
-            meshSource,
-            meshTarget,
+            srcMesh,
+            tgtMesh,
             mapMethod,
             selectedFields,
             noLagrangian
@@ -202,8 +278,8 @@ int main(int argc, char *argv[])
     {
         mapSubMesh
         (
-            meshSource,
-            meshTarget,
+            srcMesh,
+            tgtMesh,
             patchMap,
             cuttingPatches,
             mapMethod,