postProcess: Stitch non-conformal couples on first time

This has required implementation of finer control of stitching in the
fvMesh read constructor and readUpdate methods. Stitching is now
controlled independently of the mesh changers. Full-geometric stitching
is now always the default unless explicitly overridden in the calls to
fvMesh's read methods.

applications/utilities/postProcessing/graphics/PVReaders/vtkPVFoam/vtkPVFoam.C

@@ -144,7 +144,11 @@ int Foam::vtkPVFoam::setTime(int nRequest, const double requestTimes[])
 
         if (meshPtr_)
         {
-            if (meshPtr_->readUpdate(false) != polyMesh::UNCHANGED)
+            if
+            (
+                meshPtr_->readUpdate(fvMesh::stitchType::nonGeometric)
+             != polyMesh::UNCHANGED
+            )
             {
                 meshChanged_ = true;
             }
@@ -474,7 +478,8 @@ void Foam::vtkPVFoam::updateFoamMesh()
                 dbPtr_(),
                 IOobject::MUST_READ
             ),
-            false
+            false,
+            fvMesh::stitchType::nonGeometric
         );
 
         meshChanged_ = true;

src/finiteVolume/fvMesh/fvMesh.C

@@ -307,14 +307,14 @@ Foam::fvMesh::fvMesh
 (
     const IOobject& io,
     const bool changers,
-    const bool stitcher
+    const stitchType stitch
 )
 :
     polyMesh(io),
     surfaceInterpolation(*this),
     data(static_cast<const objectRegistry&>(*this)),
     boundary_(*this, boundaryMesh()),
-    stitcher_(nullptr),
+    stitcher_(fvMeshStitcher::New(*this, changers).ptr()),
     topoChanger_(nullptr),
     distributor_(nullptr),
     mover_(nullptr),
@@ -345,10 +345,9 @@ Foam::fvMesh::fvMesh
     }
 
     // Stitch or Re-stitch if necessary
-    if (stitcher)
+    if (stitch != stitchType::none)
     {
-        stitcher_.set(fvMeshStitcher::New(*this, changers).ptr());
-        stitcher_->connect(false, changers, true);
+        stitcher_->connect(false, stitch == stitchType::geometric, true);
     }
 
     // Construct changers
@@ -710,7 +709,10 @@ void Foam::fvMesh::reset(const fvMesh& newMesh)
 }
 
 
-Foam::polyMesh::readUpdateState Foam::fvMesh::readUpdate(const bool changers)
+Foam::polyMesh::readUpdateState Foam::fvMesh::readUpdate
+(
+    const stitchType stitch
+)
 {
     if (debug)
     {
@@ -719,9 +721,14 @@ Foam::polyMesh::readUpdateState Foam::fvMesh::readUpdate(const bool changers)
 
     polyMesh::readUpdateState state = polyMesh::readUpdate();
 
-    if (stitcher_.valid() && state != polyMesh::UNCHANGED)
+    if
+    (
+        stitcher_.valid()
+     && stitch != stitchType::none
+     && state != polyMesh::UNCHANGED
+    )
     {
-        stitcher_->disconnect(false, changers);
+        stitcher_->disconnect(false, stitch == stitchType::geometric);
     }
 
     if (state == polyMesh::TOPO_PATCH_CHANGE)
@@ -761,9 +768,14 @@ Foam::polyMesh::readUpdateState Foam::fvMesh::readUpdate(const bool changers)
         }
     }
 
-    if (stitcher_.valid() && state != polyMesh::UNCHANGED)
+    if
+    (
+        stitcher_.valid()
+     && stitch != stitchType::none
+     && state != polyMesh::UNCHANGED
+    )
     {
-        stitcher_->connect(false, changers, true);
+        stitcher_->connect(false, stitch == stitchType::geometric, true);
     }
 
     // If the mesh has been re-stitched with different geometry, then the

src/finiteVolume/fvMesh/fvMesh.H

@@ -100,6 +100,26 @@ class fvMesh
     public surfaceInterpolation,
     public data
 {
+public:
+
+    // Public data types
+
+        //- Extent to which to stitch on read and readUpdate. By default, a
+        //  full geometric stitch is performed. A non-geometric stitch can be
+        //  done as an optimisation in situations when finite volume geometry
+        //  is not needed (e.g., decomposition). Stitching can also be
+        //  prevented altogether if that is appropriate (e.g., if the mesh is
+        //  loaded for mapping in an un-stitched state).
+        enum class stitchType
+        {
+            none,
+            nonGeometric,
+            geometric
+        };
+
+
+private:
+
     // Private Data
 
         //- Boundary mesh
@@ -274,12 +294,13 @@ public:
     // Constructors
 
         //- Construct from IOobject
-        //  with the option to not instantiate the mesh changers or stitcher
+        //  with the option to not instantiate the mesh changers and the option
+        //  to prevent some or all of the stitching
         explicit fvMesh
         (
             const IOobject& io,
             const bool changers = true,
-            const bool stitcher = true
+            const stitchType stitch = stitchType::geometric
         );
 
         //- Construct from cellShapes with boundary.
@@ -340,7 +361,10 @@ public:
 
             //- Update the mesh based on the mesh files saved in time
             //  directories
-            readUpdateState readUpdate(const bool changers = true);
+            readUpdateState readUpdate
+            (
+                const stitchType stitch = stitchType::geometric
+            );
 
 
         // Access

src/fvMeshTopoChangers/meshToMesh/fvMeshTopoChangersMeshToMesh.C

@@ -151,7 +151,7 @@ bool Foam::fvMeshTopoChangers::meshToMesh::update()
                 IOobject::MUST_READ
             ),
             false,
-            false
+            fvMesh::stitchType::none
         );
 
         autoPtr<Foam::meshToMesh> mapper;

src/parallel/parallel/domainDecomposition.C

@@ -679,10 +679,12 @@ Foam::fvMesh::readUpdateState Foam::domainDecomposition::readUpdate()
     validateProcs();
 
     // Do read-update on all meshes
-    fvMesh::readUpdateState stat = completeMesh_->readUpdate(false);
+    fvMesh::readUpdateState stat =
+        completeMesh_->readUpdate(fvMesh::stitchType::nonGeometric);
     forAll(runTimes_.procTimes(), proci)
     {
-        fvMesh::readUpdateState procStat = procMeshes_[proci].readUpdate(false);
+        fvMesh::readUpdateState procStat =
+            procMeshes_[proci].readUpdate(fvMesh::stitchType::nonGeometric);
         if (procStat > stat)
         {
             stat = procStat;