BUG: misleading error message in finiteArea construct

- the default (uninitialised) value for edge connections of -1
  could be confused with a tagged finiteArea patch, which used
  (-patchid-1) encoding. This would lead to messages about erroneous
  processor-processor addressing, but is in fact an mismatched edge
  connection.

  Now tag the finiteArea patch as (-patchid-2) to avoid this ambiguity
  and correctly generate an "Undefined connection:" message instead.

  Properly flush the VTP writers before raising a FatalError
  to ensure that they are not prematurely truncated.

Open Point:

  The base problem of "Undefined connection:" is largely related to
  multiply-connected face edges (ie, from the underlying volume mesh).
  Not easily remedied in the finiteArea generation.

TUT: basic finiteArea setup on motorBike

src/finiteArea/faMesh/faMesh.H

@@ -101,11 +101,11 @@ class faMesh
 {
     // Private (internal) classes/structures
 
-        //- A (proc, patchi, patchEdgei) tuple used internally for managing
+        //- A (proc, patchi, patchEdgei, meshFacei) tuple used internally
-        //- patch/patch bookkeeping during construction.
+        //- for managing patch/patch bookkeeping during construction.
-        //  Finite-area patches are stored with negated indices, which makes
+        //  Finite-area patches are stored with negated indices (offset -2),
-        //  them readily identifiable and always sort before normal patches.
+        //  which makes them readily identifiable and always sort before normal
-        //  Note
+        //  patches.
         struct patchTuple
         :
             public FixedList<label, 4>
@@ -150,17 +150,17 @@ class faMesh
                 meshFacei(-1);
             }
 
-            //- Valid if proc and edge are non-negative
+            //- Valid if proc and patch (or patch edge) are non-negative
-            bool valid() const noexcept
+            bool valid() const
             {
-                return (procNo() >= 0 && patchEdgei() >= 0);
+                return (procNo() >= 0 && patchi() != -1);
             }
 
             // Processor is the first sort index
             label procNo() const { return (*this)[0]; }
             void procNo(label val) { (*this)[0] = val; }
 
-            // PatchId (-ve for finiteArea patches) is the second sort index
+            // PatchId is the second sort index (finiteArea patches are < -1)
             label patchi() const { return (*this)[1]; }
             void patchi(label val) { (*this)[1] = val; }
 
@@ -177,25 +177,25 @@ class faMesh
             label realPatchi() const
             {
                 const label id = patchi();
-                return (id < 0 ? -(id + 1) : id);
+                return (id < -1 ? -(id + 2) : id);
             }
 
             //- Set patchId as finiteArea
             void faPatchi(label val)
             {
-                patchi(-(val + 1));
+                patchi(-(val + 2));
             }
 
-            //- Considered to be finiteArea if patchi < 0
+            //- Considered to be finiteArea if (patchi < -1)
             bool is_finiteArea() const noexcept
             {
-                return (patchi() < 0);
+                return (patchi() < -1);
             }
 
             //- Considered to be processor local
-            bool is_localProc() const noexcept
+            bool is_localProc() const
             {
-                return (procNo() == Pstream::myProcNo());
+                return (procNo() == UPstream::myProcNo());
             }
         };
 

src/finiteArea/faMesh/faMeshPatches.C

@@ -120,9 +120,7 @@ Foam::faPatchList Foam::faMesh::createPatchList
         const dictionary& patchDict = dEntry.dict();
 
         // Add entry
-        faPatchDefs.append(faPatchData());
+        auto& patchDef = faPatchDefs.emplace_back();
-
-        auto& patchDef = faPatchDefs.last();
         patchDef.name_ = dEntry.keyword();
         patchDef.type_ = patchDict.get<word>("type");
 
@@ -156,9 +154,7 @@ Foam::faPatchList Foam::faMesh::createPatchList
     // Additional empty placeholder patch?
     if (!emptyPatchName.empty())
     {
-        faPatchDefs.append(faPatchData());
+        auto& patchDef = faPatchDefs.emplace_back();
-
-        auto& patchDef = faPatchDefs.last();
         patchDef.name_ = emptyPatchName;
         patchDef.type_ = "empty";
     }
@@ -168,9 +164,7 @@ Foam::faPatchList Foam::faMesh::createPatchList
     // Placeholder for any undefined edges
     const label undefPatchIndex = faPatchDefs.size();
     {
-        faPatchDefs.append(faPatchData());
+        auto& patchDef = faPatchDefs.emplace_back();
-
-        auto& patchDef = faPatchDefs.last();
         patchDef.name_ = "undefined";
         patchDef.type_ = "patch";
 
@@ -207,7 +201,6 @@ Foam::faPatchList Foam::faMesh::createPatchList
     Map<labelHashSet> procConnections;
     labelHashSet patchDefsUsed;
 
-    label nBadEdges(0);
     labelHashSet badEdges(2*bndEdgeConnections.size());
 
     forAll(bndEdgeConnections, connecti)
@@ -218,17 +211,26 @@ Foam::faPatchList Foam::faMesh::createPatchList
 
         edge patchPair;
 
-        if (a.is_finiteArea())
+        if (!a.valid() || !b.valid())
+        {
+            // Skip checking pairs where either is not valid
+            continue;
+        }
+        else if (a.is_finiteArea())
         {
             if (b.is_finiteArea())
             {
-                // A processor-processor connection
+                // Expecting an inter-processor connection
+
                 if (a.procNo() == b.procNo())
                 {
+                    // An intra-processor connection (should not be possible)
                     FatalErrorInFunction
                         << "Processor-processor addressing error:" << nl
                         << "Both connections have the same processor: "
                         << a.procNo() << nl
+                        << "Connecting patches "
+                        << a.realPatchi() << " and " << b.realPatchi() << nl
                         << abort(FatalError);
                 }
                 else if (a.is_localProc())
@@ -323,22 +325,38 @@ Foam::faPatchList Foam::faMesh::createPatchList
                         << "(patch:" << a.realPatchi()
                         << " face:" << a.meshFacei()
                         << ") and (patch:" << b.realPatchi()
-                        << " face:" << b.meshFacei() << ") connects: "
+                        << " face:" << b.meshFacei() << ")  patch:"
-                        << pbm[a.realPatchi()].name() << " to "
+                        <<
-                        << pbm[b.realPatchi()].name() << nl;
+                        (
+                            a.realPatchi() >= 0
+                          ? pbm[a.realPatchi()].name()
+                          : word::null
+                        )
+                        << " and patch:"
+                        <<
+                        (
+                            b.realPatchi() >= 0
+                          ? pbm[b.realPatchi()].name()
+                          : word::null
+                        )
+                        << nl;
                 }
             }
         }
 
-        if ((nBadEdges = returnReduce(badEdges.size(), sumOp<label>())) != 0)
+        if (returnReduceOr(badEdges.size()))
         {
             // Report directly as Info, not InfoInFunction
             // since it can also be an expected result when
             // nWarnUndefinedPatch == 0
-            Info<< "Had " << nBadEdges << '/'
+            Info<< nl
+                << "Had "
+                << returnReduce(badEdges.size(), sumOp<label>()) << '/'
                 << returnReduce(patch().nBoundaryEdges(), sumOp<label>())
                 << " undefined edge connections, added to defaultPatch: "
-                << faPatchDefs[undefPatchIndex].name_ << nl;
+                << faPatchDefs[undefPatchIndex].name_ << nl << nl
+                << "==> Could indicate a non-manifold patch geometry" << nl
+                << nl;
 
             if (nWarnUndefinedPatch)
             {
@@ -378,10 +396,9 @@ Foam::faPatchList Foam::faMesh::createPatchList
             procToDefLookup.insert(otherProci, patchDefi);
 
             // Add entry
-            faPatchDefs.append(faPatchData());
+            auto& patchDef = faPatchDefs.emplace_back();
-            auto& patchDef = faPatchDefs.last();
 
-            patchDef.assign_coupled(Pstream::myProcNo(), otherProci);
+            patchDef.assign_coupled(UPstream::myProcNo(), otherProci);
         }
     }
 

src/finiteArea/faMesh/faMeshTopology.C

@@ -30,6 +30,7 @@ License
 #include "globalMeshData.H"
 #include "indirectPrimitivePatch.H"
 #include "edgeHashes.H"
+#include "syncTools.H"
 #include "foamVtkLineWriter.H"
 #include "foamVtkIndPatchWriter.H"
 
@@ -88,7 +89,6 @@ Foam::faMesh::getBoundaryEdgeConnections() const
     // Map edges (mesh numbering) back to a boundary index
     EdgeMap<label> edgeToBoundaryIndex(2*nBoundaryEdges);
 
-    label nBadEdges(0);
     labelHashSet badEdges(2*nBoundaryEdges);
 
     {
@@ -102,7 +102,7 @@ Foam::faMesh::getBoundaryEdgeConnections() const
 
             void clear()
             {
-                Foam::edge::clear();
+                Foam::edge::clear();  // ie, (-1, -1)
                 patchEdgei_ = -1;
                 meshFacei_ = -1;
             }
@@ -114,7 +114,6 @@ Foam::faMesh::getBoundaryEdgeConnections() const
             << "Determining required boundary edge connections, "
             << "resolving locally attached boundary edges." << endl;
 
-
         // Pass 1:
         // - setup lookup (edge -> bnd index)
         // - add owner patch for each boundary edge
@@ -148,7 +147,7 @@ Foam::faMesh::getBoundaryEdgeConnections() const
             {
                 auto& tuple = bndEdgeConnections[bndEdgei].first();
 
-                tuple.procNo(Pstream::myProcNo());
+                tuple.procNo(UPstream::myProcNo());
                 tuple.faPatchi(patchId);  // Tag as finiteArea patch
                 tuple.patchEdgei(patchEdgei);
                 tuple.meshFacei(meshFacei);
@@ -165,7 +164,7 @@ Foam::faMesh::getBoundaryEdgeConnections() const
             }
         }
 
-        if ((nBadEdges = returnReduce(badEdges.size(), sumOp<label>())) != 0)
+        if (returnReduceOr(badEdges.size()))
         {
             edgeList dumpEdges(patch().edges(), badEdges.sortedToc());
 
@@ -186,9 +185,15 @@ Foam::faMesh::getBoundaryEdgeConnections() const
             writer.beginCellData();
             writer.writeProcIDs();
 
+            InfoInFunction
+                << "(debug) wrote " << writer.output().name() << nl;
+
+            writer.close();  // Flush writer before raising FatalError
+
             FatalErrorInFunction
                 << "Boundary edges not singly connected: "
-                << nBadEdges << '/' << nBoundaryEdges << nl;
+                << returnReduce(badEdges.size(), sumOp<label>()) << '/'
+                << nBoundaryEdges << nl;
 
             printPatchEdges
             (
@@ -197,9 +202,6 @@ Foam::faMesh::getBoundaryEdgeConnections() const
                 badEdges.sortedToc()
             );
 
-            InfoInFunction
-                << "(debug) wrote " << writer.output().name() << nl;
-
             FatalError << abort(FatalError);
         }
         badEdges.clear();
@@ -263,10 +265,12 @@ Foam::faMesh::getBoundaryEdgeConnections() const
             }
         }
 
-        if ((nBadEdges = returnReduce(badEdges.size(), sumOp<label>())) != 0)
+        if (returnReduceOr(badEdges.size()))
         {
             FatalErrorInFunction
-                << "Had " << nBadEdges
+                << "Had "
+                << returnReduce(badEdges.size(), sumOp<label>()) << '/'
+                << nBoundaryEdges
                 << " boundary edges with missing or multiple edge connections"
                 << abort(FatalError);
         }
@@ -275,22 +279,36 @@ Foam::faMesh::getBoundaryEdgeConnections() const
         badEdges.clear();
         for (label bndEdgei = 0; bndEdgei < nBoundaryEdges; ++bndEdgei)
         {
+            // Primary bookkeeping
+            auto& tuple = bndEdgeConnections[bndEdgei].second();
+
+            // Local bookkeeping
             const auto& pairing = patchPairings[bndEdgei];
             const label nbrPatchi = pairing.second();
             const label nbrPatchEdgei = pairing.patchEdgei_;
             const label nbrMeshFacei = pairing.meshFacei_;
 
-            if (nbrMeshFacei >= 0)
+            if (nbrMeshFacei >= 0)  // Additional safety
             {
-                // Add into primary bookkeeping
+                if (nbrPatchi >= 0)
-                auto& tuple = bndEdgeConnections[bndEdgei].second();
+                {
-
+                    // Local connection
-                tuple.procNo(Pstream::myProcNo());
+                    tuple.procNo(UPstream::myProcNo());
                     tuple.patchi(nbrPatchi);
                     tuple.patchEdgei(nbrPatchEdgei);
                     tuple.meshFacei(nbrMeshFacei);
                 }
-            else if (!Pstream::parRun())
+                else
+                {
+                    // No local connection.
+                    // Is likely to be a processor connection
+                    tuple.procNo(UPstream::myProcNo());
+                    tuple.patchi(-1);
+                    tuple.patchEdgei(-1);
+                    tuple.meshFacei(-1);
+                }
+            }
+            else if (!UPstream::parRun())
             {
                 badEdges.insert(nInternalEdges + bndEdgei);
             }
@@ -301,12 +319,11 @@ Foam::faMesh::getBoundaryEdgeConnections() const
     // ~~~~~~
     // Serial - can return already
     // ~~~~~~
-    if (!Pstream::parRun())
+    if (!UPstream::parRun())
     {
         // Verbose report of missing edges - in serial
 
-        nBadEdges = badEdges.size();
+        if (returnReduceOr(badEdges.size()))
-        if (nBadEdges)
         {
             edgeList dumpEdges(patch().edges(), badEdges.sortedToc());
 
@@ -327,9 +344,15 @@ Foam::faMesh::getBoundaryEdgeConnections() const
             writer.beginCellData();
             writer.writeProcIDs();
 
+            InfoInFunction
+                << "(debug) wrote " << writer.output().name() << nl;
+
+            writer.close();  // Flush writer before raising FatalError
+
             FatalErrorInFunction
                 << "Boundary edges with missing/invalid neighbours: "
-                << nBadEdges << '/' << nBoundaryEdges << nl;
+                << returnReduce(badEdges.size(), sumOp<label>()) << '/'
+                << nBoundaryEdges << nl;
 
             printPatchEdges
             (
@@ -338,9 +361,6 @@ Foam::faMesh::getBoundaryEdgeConnections() const
                 badEdges.sortedToc()
             );
 
-            InfoInFunction
-                << "(debug) wrote " << writer.output().name() << nl;
-
             FatalError << abort(FatalError);
         }
 
@@ -430,7 +450,7 @@ Foam::faMesh::getBoundaryEdgeConnections() const
                 auto& gathered = gatheredConnections[cppEdgei];
                 gathered.setCapacity(2);
                 gathered.resize(1);
-                auto& tuple = gathered.last();
+                auto& tuple = gathered.back();
 
                 tuple = bndEdgeConnections[bndEdgei].first();
             }
@@ -487,9 +507,9 @@ Foam::faMesh::getBoundaryEdgeConnections() const
                 auto& gathered = gatheredConnections[cppEdgei];
                 gathered.setCapacity(2);
                 gathered.resize(1);
-                auto& tuple = gathered.last();
+                auto& tuple = gathered.back();
 
-                tuple.procNo(Pstream::myProcNo());
+                tuple.procNo(UPstream::myProcNo());
                 tuple.patchi(patchi);
                 tuple.patchEdgei(patchEdgei);
                 tuple.meshFacei(meshFacei);
@@ -502,10 +522,11 @@ Foam::faMesh::getBoundaryEdgeConnections() const
         }
     }
 
-    if ((nBadEdges = returnReduce(badEdges.size(), sumOp<label>())) != 0)
+    if (returnReduceOr(badEdges.size()))
     {
         FatalErrorInFunction
-            << "Had " << nBadEdges << " coupled boundary edges"
+            << "Had " << returnReduce(badEdges.size(), sumOp<label>())
+            << " coupled boundary edges"
             << " with missing or multiple edge connections"
             << abort(FatalError);
     }
@@ -623,7 +644,7 @@ Foam::faMesh::getBoundaryEdgeConnections() const
     }
 
     // Verbose report of missing edges
-    if ((nBadEdges = returnReduce(badEdges.size(), sumOp<label>())) != 0)
+    if (returnReduceOr(badEdges.size()))
     {
         edgeList dumpEdges(patch().edges(), badEdges.sortedToc());
 
@@ -644,9 +665,15 @@ Foam::faMesh::getBoundaryEdgeConnections() const
         writer.beginCellData();
         writer.writeProcIDs();
 
+        InfoInFunction
+            << "(debug) wrote " << writer.output().name() << nl;
+
+        writer.close();  // Flush writer before raising FatalError
+
         FatalErrorInFunction
             << "Boundary edges with missing/invalid neighbours: "
-            << nBadEdges << '/' << nBoundaryEdges << nl;
+            << returnReduce(badEdges.size(), sumOp<label>()) << '/'
+            << nBoundaryEdges << nl;
 
         printPatchEdges
         (
@@ -655,9 +682,6 @@ Foam::faMesh::getBoundaryEdgeConnections() const
             badEdges.sortedToc()
         );
 
-        InfoInFunction
-            << "(debug) wrote " << writer.output().name() << nl;
-
         FatalError << abort(FatalError);
     }
 
@@ -723,7 +747,7 @@ void Foam::faMesh::setBoundaryConnections
         }
     }
 
-    label nInvalid = 0;
+    label nInvalid(0);
     for (const auto& connection : bndConnect)
     {
         if (connection.first() < 0 || connection.second() < 0)
@@ -732,15 +756,49 @@ void Foam::faMesh::setBoundaryConnections
         }
     }
 
-    if (Pstream::parRun())
+    if (returnReduceOr(nInvalid))
     {
-        reduce(nInvalid, sumOp<label>());
+        labelHashSet badEdges(2*nInvalid);
+
+        forAll(bndConnect, bndEdgei)
+        {
+            if
+            (
+                bndConnect[bndEdgei].first() < 0
+             || bndConnect[bndEdgei].second() < 0
+            )
+            {
+                badEdges.insert(nInternalEdges + bndEdgei);
+            }
         }
 
-    if (nInvalid)
+        edgeList dumpEdges(patch().edges(), badEdges.sortedToc());
-    {
+
+        vtk::lineWriter writer
+        (
+            patch().localPoints(),
+            dumpEdges,
+            fileName
+            (
+                mesh().time().globalPath()
+              / ("faMesh-construct.invalidMatches")
+            )
+        );
+
+        writer.writeGeometry();
+
+        // CellData
+        writer.beginCellData();
+        writer.writeProcIDs();
+
+        InfoInFunction
+            << "(debug) wrote " << writer.output().name() << nl;
+
+        writer.close();  // Flush writer before raising FatalError
+
         FatalErrorInFunction
-            << "Did not properly match " << nInvalid
+            << "Did not properly match "
+            << returnReduce(nInvalid, sumOp<label>())
             << " boundary edges" << nl
             << abort(FatalError);
     }
@@ -759,7 +817,7 @@ Foam::labelList Foam::faMesh::boundaryProcs() const
 {
     const auto& connections = this->boundaryConnections();
 
-    labelHashSet procsUsed(2*Pstream::nProcs());
+    labelHashSet procsUsed(2*UPstream::nProcs());
 
     for (const labelPair& tuple : connections)
     {
@@ -767,7 +825,7 @@ Foam::labelList Foam::faMesh::boundaryProcs() const
     }
 
     procsUsed.erase(-1);  // placeholder value
-    procsUsed.erase(Pstream::myProcNo());
+    procsUsed.erase(UPstream::myProcNo());
 
     return procsUsed.sortedToc();
 }
@@ -777,14 +835,14 @@ Foam::List<Foam::labelPair> Foam::faMesh::boundaryProcSizes() const
 {
     const auto& connections = this->boundaryConnections();
 
-    Map<label> procCount(2*Pstream::nProcs());
+    Map<label> procCount(2*UPstream::nProcs());
 
     for (const labelPair& tuple : connections)
     {
         ++procCount(tuple.first());
     }
     procCount.erase(-1);  // placeholder value
-    procCount.erase(Pstream::myProcNo());
+    procCount.erase(UPstream::myProcNo());
 
     // Flatten as list
     List<labelPair> output(procCount.size());

tutorials/incompressible/simpleFoam/motorBike/system/decomposeParDict-random

@@ -0,0 +1,22 @@
+/*--------------------------------*- C++ -*----------------------------------*\
+| =========                 |                                                 |
+| \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
+|  \\    /   O peration     | Version:  v2306                                 |
+|   \\  /    A nd           | Website:  www.openfoam.com                      |
+|    \\/     M anipulation  |                                                 |
+\*---------------------------------------------------------------------------*/
+FoamFile
+{
+    version     2.0;
+    format      ascii;
+    class       dictionary;
+    object      decomposeParDict;
+}
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+numberOfSubdomains 3;
+
+method          random;
+
+
+// ************************************************************************* //

tutorials/incompressible/simpleFoam/motorBike/system/faMeshDefinition

@@ -0,0 +1,30 @@
+/*--------------------------------*- C++ -*----------------------------------*\
+| =========                 |                                                 |
+| \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
+|  \\    /   O peration     | Version:  v2306                                 |
+|   \\  /    A nd           | Website:  www.openfoam.com                      |
+|    \\/     M anipulation  |                                                 |
+\*---------------------------------------------------------------------------*/
+FoamFile
+{
+    version     2.0;
+    format      ascii;
+    class       dictionary;
+    object      faMeshDefinition;
+}
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+polyMeshPatches   (motorBikeGroup);
+
+boundary
+{
+    bottom
+    {
+        type                patch;
+        // ownerPolyPatch      motorBikeGroup;
+        neighbourPolyPatch  lowerWall;
+    }
+}
+
+
+// ************************************************************************** //

tutorials/incompressible/simpleFoam/motorBike/system/faSchemes

@@ -0,0 +1,32 @@
+/*--------------------------------*- C++ -*----------------------------------*\
+| =========                 |                                                 |
+| \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
+|  \\    /   O peration     | Version:  v2306                                 |
+|   \\  /    A nd           | Website:  www.openfoam.com                      |
+|    \\/     M anipulation  |                                                 |
+\*---------------------------------------------------------------------------*/
+FoamFile
+{
+    version     2.0;
+    format      ascii;
+    class       dictionary;
+    object      faSchemes;
+}
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+ddtSchemes {}
+
+gradSchemes {}
+
+divSchemes {}
+
+laplacianSchemes {}
+
+interpolationSchemes {}
+
+lnGradSchemes {}
+
+fluxRequired {}
+
+
+// ************************************************************************* //

tutorials/incompressible/simpleFoam/motorBike/system/faSolution

@@ -0,0 +1,19 @@
+/*--------------------------------*- C++ -*----------------------------------*\
+| =========                 |                                                 |
+| \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
+|  \\    /   O peration     | Version:  v2306                                 |
+|   \\  /    A nd           | Website:  www.openfoam.com                      |
+|    \\/     M anipulation  |                                                 |
+\*---------------------------------------------------------------------------*/
+FoamFile
+{
+    version     2.0;
+    format      ascii;
+    class       dictionary;
+    object      faSolution;
+}
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+solvers {}
+
+// ************************************************************************* //