ENH: use offsets from CoherentMesh to remove communication (globalIndex) in OFCstream::writeGlobalGeometricField

- extended interface of Foam::CoherentMesh to access to boundary patch offsets
- modified and extended interface of Foam::Offsets

src/finiteVolume/fields/surfaceFields/surfaceFields.C

@@ -52,7 +52,7 @@ defineTemplateTypeNameAndDebug(surfaceTensorField, 0);
 template<>
 label IFCstream::coherentFieldSize<fvsPatchField, surfaceMesh>()
 {
-    return coherentMesh_.internalSurfaceFieldOffsets().size();
+    return coherentMesh_.internalSurfaceFieldOffsets().count();
 }
 
 

src/finiteVolume/fields/surfaceFields/surfaceFieldsI.H

@@ -417,6 +417,7 @@ Foam::OFCstream<Type, Foam::fvsPatchField, Foam::surfaceMesh>::OFCstream
 template<class Type>
 Foam::OFCstream<Type, Foam::fvsPatchField, Foam::surfaceMesh>::~OFCstream()
 {
+    internalFieldOffsets_ = coherentMesh_.internalSurfaceFieldOffsets();
     combineCoherentInternal();
     this->removeProcPatchesFromDict();
     this->writeGlobalGeometricField();

src/foam/db/IOstreams/SliceStreams/OFCstream.C

@@ -342,6 +342,13 @@ void Foam::OFCstreamBase::writeGlobalGeometricField()
     }
     sliceStreamPtr->access("fields", path);
 
+    std::vector<Offsets> offsets({internalFieldOffsets_});
+    const auto& patchOffsets = coherentMesh_.patchOffsets();
+    for (Offsets off : patchOffsets)
+    {
+        offsets.push_back(off);
+    }
+
     forAll(fieldDataEntries, i)
     {
         fieldDataEntry& fde = *(fieldDataEntries[i]);
@@ -355,12 +362,11 @@ void Foam::OFCstreamBase::writeGlobalGeometricField()
         // processorXX.
         if (!fde.uniform())
         {
-            const label nElems = fde.uList().size(); //nElems();
             const label nCmpts = fde.uList().nComponents();
 
-            const globalIndex bgi(nElems);
-            const label nGlobalElems = bgi.size();
-            const label elemOffset = bgi.offset(Pstream::myProcNo());
+            const label nGlobalElems = offsets[i].size();
+            const label elemOffset = offsets[i].offset();
+            const label nElems = offsets[i].count();
 
             // Write to engine
             sliceStreamPtr->put

src/foam/db/IOstreams/SliceStreams/OFCstream.H

@@ -65,6 +65,7 @@ protected:
 
         fileName pathname_;
         CoherentMesh& coherentMesh_;
+        Offsets internalFieldOffsets_;
 
         //- Dictionary holding both entries for the ASCII file and pointer,
         //  size data for the BLOBs.
@@ -208,6 +209,7 @@ public:
     //- Destructor
     virtual ~OFCstream()
     {
+        internalFieldOffsets_ = coherentMesh_.cellOffsets();
         this->removeProcPatchesFromDict();
         this->writeGlobalGeometricField();
     }

src/foam/meshes/polyMesh/CoherentMesh/CoherentMesh.H

@@ -164,6 +164,11 @@ public:
         return procBoundaryIDs_;
     }
 
+    inline const std::vector<Offsets>& patchOffsets() const
+    {
+        return boundarySurfacePatchOffsets_;
+    }
+
     void polyNeighbours(labelList&);
 
     void polyOwner(labelList&);

src/foam/meshes/polyMesh/CoherentMesh/Offsets.C

@@ -84,12 +84,30 @@ Foam::label Foam::Offsets::count(Foam::label myProcNo) const
 }
 
 
-Foam::label Foam::Offsets::size() const
+Foam::label Foam::Offsets::count() const
 {
     return count(Pstream::myProcNo());
 }
 
 
+Foam::label Foam::Offsets::offset(Foam::label myProcNo) const
+{
+    return lowerBound(myProcNo);
+}
+
+
+Foam::label Foam::Offsets::offset() const
+{
+    return offset(Pstream::myProcNo());
+}
+
+
+Foam::label Foam::Offsets::size() const
+{
+    return upperBound(Pstream::nProcs()-1);
+}
+
+
 Foam::Offsets::iterator Foam::Offsets::begin()
 {
     return offset_pairs_.begin();

src/foam/meshes/polyMesh/CoherentMesh/Offsets.H

@@ -88,6 +88,16 @@ public:
     // Return the difference between lower and upper bound
     label count(label) const;
 
+    // Return the count for this rank
+    label count() const;
+
+    // Return the lower bound
+    label offset(label) const;
+
+    // Return the offset for this rank
+    label offset() const;
+
+    // Return the global size
     label size() const;
 
     iterator begin();