diff --git a/src/dummyThirdParty/kahipDecomp/dummyKahipDecomp.C b/src/dummyThirdParty/kahipDecomp/dummyKahipDecomp.C
index 6e147e2626..c0e7d8f361 100644
--- a/src/dummyThirdParty/kahipDecomp/dummyKahipDecomp.C
+++ b/src/dummyThirdParty/kahipDecomp/dummyKahipDecomp.C
@@ -2,7 +2,7 @@
   =========                 |
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     |
-    \\  /    A nd           | Copyright (C) 2017 OpenCFD Ltd.
+    \\  /    A nd           | Copyright (C) 2017-2018 OpenCFD Ltd.
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
 License
@@ -60,7 +60,7 @@ Foam::label Foam::kahipDecomp::decomposeSerial
     const labelUList& xadj,
     const UList<scalar>& cellWeights,
     List<label>& decomp
-)
+) const
 {
     FatalErrorInFunction
         << notImplementedMessage << exit(FatalError);
diff --git a/src/dummyThirdParty/metisDecomp/dummyMetisDecomp.C b/src/dummyThirdParty/metisDecomp/dummyMetisDecomp.C
index c5f8e3ba9a..f72d4fcbb6 100644
--- a/src/dummyThirdParty/metisDecomp/dummyMetisDecomp.C
+++ b/src/dummyThirdParty/metisDecomp/dummyMetisDecomp.C
@@ -3,7 +3,7 @@
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     |
     \\  /    A nd           | Copyright (C) 2011-2015 OpenFOAM Foundation
-     \\/     M anipulation  |
+     \\/     M anipulation  | Copyright (C) 2018 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -60,7 +60,7 @@ Foam::label Foam::metisDecomp::decomposeSerial
     const labelUList& xadj,
     const UList<scalar>& cellWeights,
     List<label>& decomp
-)
+) const
 {
     FatalErrorInFunction
         << notImplementedMessage << exit(FatalError);
diff --git a/src/dummyThirdParty/ptscotchDecomp/dummyPtscotchDecomp.C b/src/dummyThirdParty/ptscotchDecomp/dummyPtscotchDecomp.C
index 5a756b477f..44749f8e2e 100644
--- a/src/dummyThirdParty/ptscotchDecomp/dummyPtscotchDecomp.C
+++ b/src/dummyThirdParty/ptscotchDecomp/dummyPtscotchDecomp.C
@@ -3,7 +3,7 @@
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     |
     \\  /    A nd           | Copyright (C) 2011-2015 OpenFOAM Foundation
-     \\/     M anipulation  |
+     \\/     M anipulation  | Copyright (C) 2018 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -54,7 +54,7 @@ namespace Foam
 
 // * * * * * * * * * * * * * Private Member Functions  * * * * * * * * * * * //
 
-void Foam::ptscotchDecomp::graphPath(const polyMesh& unused)
+void Foam::ptscotchDecomp::graphPath(const polyMesh& unused) const
 {}
 
 
@@ -124,7 +124,7 @@ Foam::labelList Foam::ptscotchDecomp::decompose
     const polyMesh& mesh,
     const pointField& points,
     const scalarField& pointWeights
-)
+) const
 {
     FatalErrorInFunction
         << notImplementedMessage << exit(FatalError);
@@ -139,7 +139,7 @@ Foam::labelList Foam::ptscotchDecomp::decompose
     const labelList& agglom,
     const pointField& agglomPoints,
     const scalarField& pointWeights
-)
+) const
 {
     FatalErrorInFunction
         << notImplementedMessage << exit(FatalError);
@@ -153,7 +153,7 @@ Foam::labelList Foam::ptscotchDecomp::decompose
     const labelListList& globalCellCells,
     const pointField& cellCentres,
     const scalarField& cWeights
-)
+) const
 {
     FatalErrorInFunction
         << notImplementedMessage << exit(FatalError);
diff --git a/src/dummyThirdParty/scotchDecomp/dummyScotchDecomp.C b/src/dummyThirdParty/scotchDecomp/dummyScotchDecomp.C
index 9aa8e20ec0..02ae756388 100644
--- a/src/dummyThirdParty/scotchDecomp/dummyScotchDecomp.C
+++ b/src/dummyThirdParty/scotchDecomp/dummyScotchDecomp.C
@@ -3,7 +3,7 @@
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     |
     \\  /    A nd           | Copyright (C) 2011-2015 OpenFOAM Foundation
-     \\/     M anipulation  |
+     \\/     M anipulation  | Copyright (C) 2018 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -53,7 +53,7 @@ namespace Foam
 
 // * * * * * * * * * * * * * Private Member Functions  * * * * * * * * * * * //
 
-void Foam::scotchDecomp::graphPath(const polyMesh& unused)
+void Foam::scotchDecomp::graphPath(const polyMesh& unused) const
 {}
 
 
@@ -67,7 +67,7 @@ Foam::label Foam::scotchDecomp::decomposeSerial
     const labelUList& xadj,
     const UList<scalar>& cWeights,
     List<label>& decomp
-)
+) const
 {
     FatalErrorInFunction
         << notImplementedMessage << exit(FatalError);
@@ -104,7 +104,7 @@ Foam::labelList Foam::scotchDecomp::decompose
     const polyMesh& mesh,
     const pointField& points,
     const scalarField& pointWeights
-)
+) const
 {
     FatalErrorInFunction
         << notImplementedMessage << exit(FatalError);
@@ -119,7 +119,7 @@ Foam::labelList Foam::scotchDecomp::decompose
     const labelList& agglom,
     const pointField& agglomPoints,
     const scalarField& pointWeights
-)
+) const
 {
     FatalErrorInFunction
         << notImplementedMessage << exit(FatalError);
@@ -133,7 +133,7 @@ Foam::labelList Foam::scotchDecomp::decompose
     const labelListList& globalCellCells,
     const pointField& cellCentres,
     const scalarField& cWeights
-)
+) const
 {
     FatalErrorInFunction
         << notImplementedMessage << exit(FatalError);
diff --git a/src/parallel/decompose/decompositionMethods/decompositionConstraints/decompositionConstraint/decompositionConstraint.C b/src/parallel/decompose/decompositionMethods/decompositionConstraints/decompositionConstraint/decompositionConstraint.C
index 57ac5fb352..1bdd2a46b1 100644
--- a/src/parallel/decompose/decompositionMethods/decompositionConstraints/decompositionConstraint/decompositionConstraint.C
+++ b/src/parallel/decompose/decompositionMethods/decompositionConstraints/decompositionConstraint/decompositionConstraint.C
@@ -3,7 +3,7 @@
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     |
     \\  /    A nd           | Copyright (C) 2015-2017 OpenFOAM Foundation
-     \\/     M anipulation  | Copyright (C) 2015 OpenCFD Ltd.
+     \\/     M anipulation  | Copyright (C) 2015-2018 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -75,10 +75,4 @@ Foam::decompositionConstraint::New
 }
 
 
-// * * * * * * * * * * * * * * * * Destructor  * * * * * * * * * * * * * * * //
-
-Foam::decompositionConstraint::~decompositionConstraint()
-{}
-
-
 // ************************************************************************* //
diff --git a/src/parallel/decompose/decompositionMethods/decompositionConstraints/decompositionConstraint/decompositionConstraint.H b/src/parallel/decompose/decompositionMethods/decompositionConstraints/decompositionConstraint/decompositionConstraint.H
index 9adb44da1f..58ad56379d 100644
--- a/src/parallel/decompose/decompositionMethods/decompositionConstraints/decompositionConstraint/decompositionConstraint.H
+++ b/src/parallel/decompose/decompositionMethods/decompositionConstraints/decompositionConstraint/decompositionConstraint.H
@@ -3,7 +3,7 @@
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     |
     \\  /    A nd           | Copyright (C) 2015-2016 OpenFOAM Foundation
-     \\/     M anipulation  |
+     \\/     M anipulation  | Copyright (C) 2018 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -45,11 +45,11 @@ SourceFiles
 namespace Foam
 {
 
-// Forward declaration of classes
+// Forward declarations
 class polyMesh;
 
 /*---------------------------------------------------------------------------*\
-                Class decompositionConstraint Declaration
+                   Class decompositionConstraint Declaration
 \*---------------------------------------------------------------------------*/
 
 class decompositionConstraint
@@ -65,11 +65,11 @@ private:
 
     // Private Member Functions
 
-        //- Disallow default bitwise copy construct
-        decompositionConstraint(const decompositionConstraint&);
+        //- No copy construct
+        decompositionConstraint(const decompositionConstraint&) = delete;
 
-        //- Disallow default bitwise assignment
-        void operator=(const decompositionConstraint&);
+        //- No copy assignment
+        void operator=(const decompositionConstraint&) = delete;
 
 
 public:
@@ -102,6 +102,7 @@ public:
             const word& type
         );
 
+
     // Selectors
 
         //- Return a reference to the selected decompositionConstraint
@@ -113,7 +114,7 @@ public:
 
 
     //- Destructor
-    virtual ~decompositionConstraint();
+    virtual ~decompositionConstraint() = default;
 
 
     // Member Functions
@@ -128,9 +129,9 @@ public:
             List<labelPair>& explicitConnections
         ) const = 0;
 
-        //- Apply any additional post-decomposition constraints. Usually no
-        //  need to do anything since decomposition method should have already
-        //  obeyed the constraints
+        //- Apply any additional post-decomposition constraints.
+        //  Usually no need to do anything since decomposition method
+        //  should have already obeyed the constraints
         virtual void apply
         (
             const polyMesh& mesh,
diff --git a/src/parallel/decompose/decompositionMethods/decompositionConstraints/preserveBaffles/preserveBafflesConstraint.C b/src/parallel/decompose/decompositionMethods/decompositionConstraints/preserveBaffles/preserveBafflesConstraint.C
index d2c1b50e94..06c5f3e97a 100644
--- a/src/parallel/decompose/decompositionMethods/decompositionConstraints/preserveBaffles/preserveBafflesConstraint.C
+++ b/src/parallel/decompose/decompositionMethods/decompositionConstraints/preserveBaffles/preserveBafflesConstraint.C
@@ -3,7 +3,7 @@
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     |
     \\  /    A nd           | Copyright (C) 2015-2016 OpenFOAM Foundation
-     \\/     M anipulation  |
+     \\/     M anipulation  | Copyright (C) 2018 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -108,18 +108,15 @@ void Foam::decompositionConstraints::preserveBafflesConstraint::add
     {
         // Convert into face-to-face addressing
         labelList faceToFace(mesh.nFaces(), -1);
-        forAll(explicitConnections, i)
+        for (const labelPair& p : explicitConnections)
         {
-            const labelPair& p = explicitConnections[i];
             faceToFace[p[0]] = p[1];
             faceToFace[p[1]] = p[0];
         }
 
         // Merge in bafflePairs
-        forAll(bafflePairs, i)
+        for (const labelPair& p : bafflePairs)
         {
-            const labelPair& p = bafflePairs[i];
-
             if (faceToFace[p[0]] == -1 && faceToFace[p[1]] == -1)
             {
                 faceToFace[p[0]] = p[1];
@@ -131,8 +128,8 @@ void Foam::decompositionConstraints::preserveBafflesConstraint::add
             }
             else
             {
-                label p0Slave = faceToFace[p[0]];
-                label p1Slave = faceToFace[p[1]];
+                const label p0Slave = faceToFace[p[0]];
+                const label p1Slave = faceToFace[p[1]];
                 IOWarningInFunction(coeffDict_)
                     << "When adding baffle between faces "
                     << p[0] << " at " << mesh.faceCentres()[p[0]]
@@ -171,10 +168,10 @@ void Foam::decompositionConstraints::preserveBafflesConstraint::add
 
     // Make sure blockedFace is uptodate
     blockedFace.setSize(mesh.nFaces(), true);
-    forAll(explicitConnections, i)
+    for (const labelPair& p : explicitConnections)
     {
-        blockedFace[explicitConnections[i].first()] = false;
-        blockedFace[explicitConnections[i].second()] = false;
+        blockedFace[p.first()] = false;
+        blockedFace[p.second()] = false;
     }
     syncTools::syncFaceList(mesh, blockedFace, andEqOp<bool>());
 }
@@ -197,33 +194,32 @@ void Foam::decompositionConstraints::preserveBafflesConstraint::apply
 
     label nChanged = 0;
 
-    forAll(bafflePairs, i)
+    for (const labelPair& baffle : bafflePairs)
     {
-        const labelPair& baffle = bafflePairs[i];
-        label f0 = baffle.first();
-        label f1 = baffle.second();
+        const label f0 = baffle.first();
+        const label f1 = baffle.second();
 
         const label procI = decomposition[mesh.faceOwner()[f0]];
 
         if (mesh.isInternalFace(f0))
         {
-            label nei0 = mesh.faceNeighbour()[f0];
+            const label nei0 = mesh.faceNeighbour()[f0];
             if (decomposition[nei0] != procI)
             {
                 decomposition[nei0] = procI;
-                nChanged++;
+                ++nChanged;
             }
         }
 
-        label own1 = mesh.faceOwner()[f1];
+        const label own1 = mesh.faceOwner()[f1];
         if (decomposition[own1] != procI)
         {
             decomposition[own1] = procI;
-            nChanged++;
+            ++nChanged;
         }
         if (mesh.isInternalFace(f1))
         {
-            label nei1 = mesh.faceNeighbour()[f1];
+            const label nei1 = mesh.faceNeighbour()[f1];
             if (decomposition[nei1] != procI)
             {
                 decomposition[nei1] = procI;
diff --git a/src/parallel/decompose/decompositionMethods/decompositionConstraints/preserveBaffles/preserveBafflesConstraint.H b/src/parallel/decompose/decompositionMethods/decompositionConstraints/preserveBaffles/preserveBafflesConstraint.H
index e593a5af7b..3fa49b00f1 100644
--- a/src/parallel/decompose/decompositionMethods/decompositionConstraints/preserveBaffles/preserveBafflesConstraint.H
+++ b/src/parallel/decompose/decompositionMethods/decompositionConstraints/preserveBaffles/preserveBafflesConstraint.H
@@ -3,7 +3,7 @@
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     |
     \\  /    A nd           | Copyright (C) 2015-2016 OpenFOAM Foundation
-     \\/     M anipulation  |
+     \\/     M anipulation  | Copyright (C) 2018 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -53,8 +53,6 @@ class preserveBafflesConstraint
 :
     public decompositionConstraint
 {
-    // Private data
-
 public:
 
     //- Runtime type information
@@ -75,8 +73,7 @@ public:
 
 
     //- Destructor
-    virtual ~preserveBafflesConstraint()
-    {}
+    virtual ~preserveBafflesConstraint() = default;
 
 
     // Member Functions
diff --git a/src/parallel/decompose/decompositionMethods/decompositionConstraints/preserveFaceZones/preserveFaceZonesConstraint.C b/src/parallel/decompose/decompositionMethods/decompositionConstraints/preserveFaceZones/preserveFaceZonesConstraint.C
index a3858b0a25..e481aef604 100644
--- a/src/parallel/decompose/decompositionMethods/decompositionConstraints/preserveFaceZones/preserveFaceZonesConstraint.C
+++ b/src/parallel/decompose/decompositionMethods/decompositionConstraints/preserveFaceZones/preserveFaceZonesConstraint.C
@@ -3,7 +3,7 @@
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     |
     \\  /    A nd           | Copyright (C) 2015-2016 OpenFOAM Foundation
-     \\/     M anipulation  |
+     \\/     M anipulation  | Copyright (C) 2018 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -99,20 +99,20 @@ void Foam::decompositionConstraints::preserveFaceZonesConstraint::add
 
     const faceZoneMesh& fZones = mesh.faceZones();
 
-    const labelList zoneIDs = findStrings(zones_, fZones.names());
+    const labelList zoneIDs(findStrings(zones_, fZones.names()));
 
     label nUnblocked = 0;
 
-    forAll(zoneIDs, i)
+    for (const label zonei : zoneIDs)
     {
-        const faceZone& fz = fZones[zoneIDs[i]];
+        const faceZone& fz = fZones[zonei];
 
-        forAll(fz, i)
+        for (const label meshFacei : fz)
         {
-            if (blockedFace[fz[i]])
+            if (blockedFace[meshFacei])
             {
-                blockedFace[fz[i]] = false;
-                nUnblocked++;
+                blockedFace[meshFacei] = false;
+                ++nUnblocked;
             }
         }
     }
@@ -148,16 +148,17 @@ void Foam::decompositionConstraints::preserveFaceZonesConstraint::apply
 
     labelList destProc(mesh.nFaces()-mesh.nInternalFaces(), labelMax);
 
-    forAll(pbm, patchi)
+    for (const polyPatch& pp : pbm)
     {
-        const polyPatch& pp = pbm[patchi];
+        label bFacei = pp.start() - mesh.nInternalFaces();
 
         const labelUList& faceCells = pp.faceCells();
 
-        forAll(faceCells, i)
+        for (const label celli : faceCells)
         {
-            label bFaceI = pp.start()+i-mesh.nInternalFaces();
-            destProc[bFaceI] = decomposition[faceCells[i]];
+            destProc[bFacei] = decomposition[celli];
+
+            ++bFacei;
         }
     }
 
@@ -169,36 +170,34 @@ void Foam::decompositionConstraints::preserveFaceZonesConstraint::apply
 
     const faceZoneMesh& fZones = mesh.faceZones();
 
-    const labelList zoneIDs = findStrings(zones_, fZones.names());
+    const labelList zoneIDs(findStrings(zones_, fZones.names()));
 
     label nChanged = 0;
 
-    forAll(zoneIDs, i)
+    for (const label zonei : zoneIDs)
     {
-        const faceZone& fz = fZones[zoneIDs[i]];
+        const faceZone& fz = fZones[zonei];
 
-        forAll(fz, i)
+        for (const label facei : fz)
         {
-            label faceI = fz[i];
+            const label own = mesh.faceOwner()[facei];
 
-            label own = mesh.faceOwner()[faceI];
-
-            if (mesh.isInternalFace(faceI))
+            if (mesh.isInternalFace(facei))
             {
-                label nei = mesh.faceNeighbour()[faceI];
+                const label nei = mesh.faceNeighbour()[facei];
                 if (decomposition[own] != decomposition[nei])
                 {
                     decomposition[nei] = decomposition[own];
-                    nChanged++;
+                    ++nChanged;
                 }
             }
             else
             {
-                label bFaceI = faceI-mesh.nInternalFaces();
+                const label bFaceI = facei-mesh.nInternalFaces();
                 if (decomposition[own] != destProc[bFaceI])
                 {
                     decomposition[own] = destProc[bFaceI];
-                    nChanged++;
+                    ++nChanged;
                 }
             }
         }
diff --git a/src/parallel/decompose/decompositionMethods/decompositionConstraints/preservePatches/preservePatchesConstraint.C b/src/parallel/decompose/decompositionMethods/decompositionConstraints/preservePatches/preservePatchesConstraint.C
index 0ed43439c9..8333cbfd7d 100644
--- a/src/parallel/decompose/decompositionMethods/decompositionConstraints/preservePatches/preservePatchesConstraint.C
+++ b/src/parallel/decompose/decompositionMethods/decompositionConstraints/preservePatches/preservePatchesConstraint.C
@@ -3,7 +3,7 @@
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     |
     \\  /    A nd           | Copyright (C) 2015-2016 OpenFOAM Foundation
-     \\/     M anipulation  |
+     \\/     M anipulation  | Copyright (C) 2018 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -103,16 +103,18 @@ void Foam::decompositionConstraints::preservePatchesConstraint::add
 
     label nUnblocked = 0;
 
-    forAll(patchIDs, i)
+    for (const label patchi : patchIDs)
     {
-        const polyPatch& pp = pbm[patchIDs[i]];
+        const polyPatch& pp = pbm[patchi];
 
         forAll(pp, i)
         {
-            if (blockedFace[pp.start() + i])
+            const label meshFacei = pp.start() + i;
+
+            if (blockedFace[meshFacei])
             {
-                blockedFace[pp.start() + i] = false;
-                nUnblocked++;
+                blockedFace[meshFacei] = false;
+                ++nUnblocked;
             }
         }
     }
@@ -137,8 +139,7 @@ void Foam::decompositionConstraints::preservePatchesConstraint::apply
     labelList& decomposition
 ) const
 {
-    // If the decomposition has not enforced the constraint do it over
-    // here.
+    // If the decomposition has not enforced the constraint, do it over here.
 
     // Synchronise decomposition on patchIDs
     // ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
@@ -147,10 +148,8 @@ void Foam::decompositionConstraints::preservePatchesConstraint::apply
 
     labelList destProc(mesh.nFaces()-mesh.nInternalFaces(), labelMax);
 
-    forAll(pbm, patchi)
+    for (const polyPatch& pp : pbm)
     {
-        const polyPatch& pp = pbm[patchi];
-
         const labelUList& faceCells = pp.faceCells();
 
         forAll(faceCells, i)
@@ -170,9 +169,9 @@ void Foam::decompositionConstraints::preservePatchesConstraint::apply
 
     label nChanged = 0;
 
-    forAll(patchIDs, i)
+    for (const label patchi : patchIDs)
     {
-        const polyPatch& pp = pbm[patchIDs[i]];
+        const polyPatch& pp = pbm[patchi];
 
         const labelUList& faceCells = pp.faceCells();
 
@@ -183,7 +182,7 @@ void Foam::decompositionConstraints::preservePatchesConstraint::apply
             if (decomposition[faceCells[i]] != destProc[bFaceI])
             {
                 decomposition[faceCells[i]] = destProc[bFaceI];
-                nChanged++;
+                ++nChanged;
             }
         }
     }
diff --git a/src/parallel/decompose/decompositionMethods/decompositionConstraints/preservePatches/preservePatchesConstraint.H b/src/parallel/decompose/decompositionMethods/decompositionConstraints/preservePatches/preservePatchesConstraint.H
index 6a81c42472..8a6a5fe595 100644
--- a/src/parallel/decompose/decompositionMethods/decompositionConstraints/preservePatches/preservePatchesConstraint.H
+++ b/src/parallel/decompose/decompositionMethods/decompositionConstraints/preservePatches/preservePatchesConstraint.H
@@ -3,7 +3,7 @@
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     |
     \\  /    A nd           | Copyright (C) 2015-2016 OpenFOAM Foundation
-     \\/     M anipulation  |
+     \\/     M anipulation  | Copyright (C) 2018 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -48,7 +48,7 @@ namespace decompositionConstraints
 {
 
 /*---------------------------------------------------------------------------*\
-                Class preservePatchesConstraint Declaration
+                  Class preservePatchesConstraint Declaration
 \*---------------------------------------------------------------------------*/
 
 class preservePatchesConstraint
@@ -80,7 +80,6 @@ public:
         preservePatchesConstraint(const UList<wordRe>& patches);
 
 
-
     //- Destructor
     virtual ~preservePatchesConstraint() = default;
 
diff --git a/src/parallel/decompose/decompositionMethods/decompositionConstraints/refinementHistory/refinementHistoryConstraint.C b/src/parallel/decompose/decompositionMethods/decompositionConstraints/refinementHistory/refinementHistoryConstraint.C
index 2a93702410..c1af450d7f 100644
--- a/src/parallel/decompose/decompositionMethods/decompositionConstraints/refinementHistory/refinementHistoryConstraint.C
+++ b/src/parallel/decompose/decompositionMethods/decompositionConstraints/refinementHistory/refinementHistoryConstraint.C
@@ -3,7 +3,7 @@
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     |
     \\  /    A nd           | Copyright (C) 2015-2016 OpenFOAM Foundation
-     \\/     M anipulation  |
+     \\/     M anipulation  | Copyright (C) 2018 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -55,7 +55,7 @@ Foam::refinementHistoryConstraint::refinementHistoryConstraint
 {
     if (decompositionConstraint::debug)
     {
-        Info<< type() << " : setting constraints to preserve refinement history"
+        Info<< type() << " : setting constraints to refinement history"
             << endl;
     }
 }
@@ -123,7 +123,7 @@ void Foam::refinementHistoryConstraint::add
     const refinementHistory& history =
     (
         storagePtr.valid()
-      ? storagePtr()
+      ? *storagePtr
       : *refPtr
     );
 
@@ -190,7 +190,7 @@ void Foam::refinementHistoryConstraint::apply
     const refinementHistory& history =
     (
         storagePtr.valid()
-      ? storagePtr()
+      ? *storagePtr
       : *refPtr
     );
 
diff --git a/src/parallel/decompose/decompositionMethods/decompositionConstraints/refinementHistory/refinementHistoryConstraint.H b/src/parallel/decompose/decompositionMethods/decompositionConstraints/refinementHistory/refinementHistoryConstraint.H
index b4adc677a3..d544ed8eb9 100644
--- a/src/parallel/decompose/decompositionMethods/decompositionConstraints/refinementHistory/refinementHistoryConstraint.H
+++ b/src/parallel/decompose/decompositionMethods/decompositionConstraints/refinementHistory/refinementHistoryConstraint.H
@@ -3,7 +3,7 @@
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     |
     \\  /    A nd           | Copyright (C) 2015-2016 OpenFOAM Foundation
-     \\/     M anipulation  |
+     \\/     M anipulation  | Copyright (C) 2018 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -43,7 +43,6 @@ SourceFiles
 namespace Foam
 {
 
-
 /*---------------------------------------------------------------------------*\
                 Class refinementHistoryConstraint Declaration
 \*---------------------------------------------------------------------------*/
@@ -52,8 +51,6 @@ class refinementHistoryConstraint
 :
     public decompositionConstraint
 {
-    // Private data
-
 public:
 
     //- Runtime type information
@@ -74,8 +71,7 @@ public:
 
 
     //- Destructor
-    virtual ~refinementHistoryConstraint()
-    {}
+    virtual ~refinementHistoryConstraint() = default;
 
 
     // Member Functions
diff --git a/src/parallel/decompose/decompositionMethods/decompositionConstraints/singleProcessorFaceSets/singleProcessorFaceSetsConstraint.H b/src/parallel/decompose/decompositionMethods/decompositionConstraints/singleProcessorFaceSets/singleProcessorFaceSetsConstraint.H
index fd4a904a95..691f5ef993 100644
--- a/src/parallel/decompose/decompositionMethods/decompositionConstraints/singleProcessorFaceSets/singleProcessorFaceSetsConstraint.H
+++ b/src/parallel/decompose/decompositionMethods/decompositionConstraints/singleProcessorFaceSets/singleProcessorFaceSetsConstraint.H
@@ -3,7 +3,7 @@
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     |
     \\  /    A nd           | Copyright (C) 2015-2016 OpenFOAM Foundation
-     \\/     M anipulation  |
+     \\/     M anipulation  | Copyright (C) 2018 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -83,8 +83,7 @@ public:
 
 
     //- Destructor
-    virtual ~singleProcessorFaceSetsConstraint()
-    {}
+    virtual ~singleProcessorFaceSetsConstraint() = default;
 
 
     // Member Functions
diff --git a/src/parallel/decompose/decompositionMethods/decompositionMethod/decompositionMethod.C b/src/parallel/decompose/decompositionMethods/decompositionMethod/decompositionMethod.C
index 1f9e404bfc..eae7f72761 100644
--- a/src/parallel/decompose/decompositionMethods/decompositionMethod/decompositionMethod.C
+++ b/src/parallel/decompose/decompositionMethods/decompositionMethod/decompositionMethod.C
@@ -424,7 +424,7 @@ Foam::labelList Foam::decompositionMethod::decompose
 (
     const polyMesh& mesh,
     const pointField& points
-)
+) const
 {
     scalarField weights(points.size(), 1.0);
 
@@ -438,7 +438,7 @@ Foam::labelList Foam::decompositionMethod::decompose
     const labelList& fineToCoarse,
     const pointField& coarsePoints,
     const scalarField& coarseWeights
-)
+) const
 {
     CompactListList<label> coarseCellCells;
     calcCellCells
@@ -478,16 +478,16 @@ Foam::labelList Foam::decompositionMethod::decompose
     const polyMesh& mesh,
     const labelList& fineToCoarse,
     const pointField& coarsePoints
-)
+) const
 {
-    scalarField cWeights(coarsePoints.size(), 1.0);
+    scalarField weights(coarsePoints.size(), 1.0);
 
     return decompose
     (
         mesh,
         fineToCoarse,
         coarsePoints,
-        cWeights
+        weights
     );
 }
 
@@ -496,11 +496,11 @@ Foam::labelList Foam::decompositionMethod::decompose
 (
     const labelListList& globalCellCells,
     const pointField& cc
-)
+) const
 {
-    scalarField cWeights(cc.size(), 1.0);
+    scalarField weights(cc.size(), 1.0);
 
-    return decompose(globalCellCells, cc, cWeights);
+    return decompose(globalCellCells, cc, weights);
 }
 
 
@@ -535,10 +535,8 @@ void Foam::decompositionMethod::calcCellCells
 
     labelList globalNeighbour(mesh.nFaces()-mesh.nInternalFaces());
 
-    forAll(patches, patchi)
+    for (const polyPatch& pp : patches)
     {
-        const polyPatch& pp = patches[patchi];
-
         if (pp.coupled() && (parallel || !isA<processorPolyPatch>(pp)))
         {
             label facei = pp.start();
@@ -551,8 +549,8 @@ void Foam::decompositionMethod::calcCellCells
                     agglom[faceOwner[facei]]
                 );
 
-                bFacei++;
-                facei++;
+                ++facei;
+                ++bFacei;
             }
         }
     }
@@ -576,10 +574,8 @@ void Foam::decompositionMethod::calcCellCells
         nFacesPerCell[nei]++;
     }
 
-    forAll(patches, patchi)
+    for (const polyPatch& pp : patches)
     {
-        const polyPatch& pp = patches[patchi];
-
         if (pp.coupled() && (parallel || !isA<processorPolyPatch>(pp)))
         {
             label facei = pp.start();
@@ -588,8 +584,8 @@ void Foam::decompositionMethod::calcCellCells
             forAll(pp, i)
             {
                 const label own = agglom[faceOwner[facei]];
+                const label globalNei = globalNeighbour[bFacei];
 
-                label globalNei = globalNeighbour[bFacei];
                 if
                 (
                    !globalAgglom.isLocal(globalNei)
@@ -599,8 +595,8 @@ void Foam::decompositionMethod::calcCellCells
                     nFacesPerCell[own]++;
                 }
 
-                facei++;
-                bFacei++;
+                ++facei;
+                ++bFacei;
             }
         }
     }
@@ -627,10 +623,8 @@ void Foam::decompositionMethod::calcCellCells
     }
 
     // For boundary faces is offsetted coupled neighbour
-    forAll(patches, patchi)
+    for (const polyPatch& pp : patches)
     {
-        const polyPatch& pp = patches[patchi];
-
         if (pp.coupled() && (parallel || !isA<processorPolyPatch>(pp)))
         {
             label facei = pp.start();
@@ -639,7 +633,6 @@ void Foam::decompositionMethod::calcCellCells
             forAll(pp, i)
             {
                 const label own = agglom[faceOwner[facei]];
-
                 const label globalNei = globalNeighbour[bFacei];
 
                 if
@@ -651,8 +644,8 @@ void Foam::decompositionMethod::calcCellCells
                     m[offsets[own] + nFacesPerCell[own]++] = globalNei;
                 }
 
-                facei++;
-                bFacei++;
+                ++facei;
+                ++bFacei;
             }
         }
     }
@@ -741,24 +734,22 @@ void Foam::decompositionMethod::calcCellCells
 
     labelList globalNeighbour(mesh.nFaces()-mesh.nInternalFaces());
 
-    forAll(patches, patchi)
+    for (const polyPatch& pp : patches)
     {
-        const polyPatch& pp = patches[patchi];
-
         if (pp.coupled() && (parallel || !isA<processorPolyPatch>(pp)))
         {
-            label faceI = pp.start();
-            label bFaceI = pp.start() - mesh.nInternalFaces();
+            label facei = pp.start();
+            label bFacei = pp.start() - mesh.nInternalFaces();
 
             forAll(pp, i)
             {
-                globalNeighbour[bFaceI] = globalAgglom.toGlobal
+                globalNeighbour[bFacei] = globalAgglom.toGlobal
                 (
-                    agglom[faceOwner[faceI]]
+                    agglom[faceOwner[facei]]
                 );
 
-                bFaceI++;
-                faceI++;
+                ++facei;
+                ++bFacei;
             }
         }
     }
@@ -782,20 +773,18 @@ void Foam::decompositionMethod::calcCellCells
         nFacesPerCell[nei]++;
     }
 
-    forAll(patches, patchi)
+    for (const polyPatch& pp : patches)
     {
-        const polyPatch& pp = patches[patchi];
-
         if (pp.coupled() && (parallel || !isA<processorPolyPatch>(pp)))
         {
-            label faceI = pp.start();
-            label bFaceI = pp.start()-mesh.nInternalFaces();
+            label facei = pp.start();
+            label bFacei = pp.start() - mesh.nInternalFaces();
 
             forAll(pp, i)
             {
-                const label own = agglom[faceOwner[faceI]];
+                const label own = agglom[faceOwner[facei]];
 
-                const label globalNei = globalNeighbour[bFaceI];
+                const label globalNei = globalNeighbour[bFacei];
                 if
                 (
                    !globalAgglom.isLocal(globalNei)
@@ -805,8 +794,8 @@ void Foam::decompositionMethod::calcCellCells
                     nFacesPerCell[own]++;
                 }
 
-                faceI++;
-                bFaceI++;
+                ++facei;
+                ++bFacei;
             }
         }
     }
@@ -840,20 +829,18 @@ void Foam::decompositionMethod::calcCellCells
     }
 
     // For boundary faces is offsetted coupled neighbour
-    forAll(patches, patchi)
+    for (const polyPatch& pp : patches)
     {
-        const polyPatch& pp = patches[patchi];
-
         if (pp.coupled() && (parallel || !isA<processorPolyPatch>(pp)))
         {
-            label faceI = pp.start();
-            label bFaceI = pp.start()-mesh.nInternalFaces();
+            label facei = pp.start();
+            label bFacei = pp.start()-mesh.nInternalFaces();
 
             forAll(pp, i)
             {
-                const label own = agglom[faceOwner[faceI]];
+                const label own = agglom[faceOwner[facei]];
 
-                const label globalNei = globalNeighbour[bFaceI];
+                const label globalNei = globalNeighbour[bFacei];
 
                 if
                 (
@@ -863,11 +850,11 @@ void Foam::decompositionMethod::calcCellCells
                 {
                     label ownIndex = offsets[own] + nFacesPerCell[own]++;
                     m[ownIndex] = globalNei;
-                    w[ownIndex] = mag(mesh.faceAreas()[faceI]);
+                    w[ownIndex] = mag(mesh.faceAreas()[facei]);
                 }
 
-                faceI++;
-                bFaceI++;
+                ++facei;
+                ++bFacei;
             }
         }
     }
@@ -946,10 +933,8 @@ void Foam::decompositionMethod::calcCellCells
 //
 //    labelList globalNeighbour(mesh.nFaces()-mesh.nInternalFaces());
 //
-//    forAll(patches, patchi)
+//    for (const polyPatch& pp : patches)
 //    {
-//        const polyPatch& pp = patches[patchi];
-//
 //        if (pp.coupled() && (parallel || !isA<processorPolyPatch>(pp)))
 //        {
 //            label facei = pp.start();
@@ -962,8 +947,8 @@ void Foam::decompositionMethod::calcCellCells
 //                    agglom[faceOwner[facei]]
 //                );
 //
-//                bFacei++;
-//                facei++;
+//                ++facei;
+//                ++bFacei;
 //            }
 //        }
 //    }
@@ -983,8 +968,8 @@ void Foam::decompositionMethod::calcCellCells
 //    {
 //        if (!blockedFace[facei])
 //        {
-//            label own = agglom[faceOwner[facei]];
-//            label nei = agglom[faceNeighbour[facei]];
+//            const label own = agglom[faceOwner[facei]];
+//            const label nei = agglom[faceNeighbour[facei]];
 //
 //            nFacesPerCell[own]++;
 //            nFacesPerCell[nei]++;
@@ -992,10 +977,8 @@ void Foam::decompositionMethod::calcCellCells
 //    }
 //
 //    // 2. Coupled faces
-//    forAll(patches, patchi)
+//    for (const polyPatch& pp : patches)
 //    {
-//        const polyPatch& pp = patches[patchi];
-//
 //        if (pp.coupled() && (parallel || !isA<processorPolyPatch>(pp)))
 //        {
 //            label facei = pp.start();
@@ -1005,9 +988,9 @@ void Foam::decompositionMethod::calcCellCells
 //            {
 //                if (!blockedFace[facei])
 //                {
-//                    label own = agglom[faceOwner[facei]];
+//                    const label own = agglom[faceOwner[facei]];
+//                    const label globalNei = globalNeighbour[bFacei];
 //
-//                    label globalNei = globalNeighbour[bFacei];
 //                    if
 //                    (
 //                       !globalAgglom.isLocal(globalNei)
@@ -1017,8 +1000,8 @@ void Foam::decompositionMethod::calcCellCells
 //                        nFacesPerCell[own]++;
 //                    }
 //
-//                    facei++;
-//                    bFacei++;
+//                    ++facei;
+//                    ++bFacei;
 //                }
 //            }
 //        }
@@ -1121,10 +1104,8 @@ void Foam::decompositionMethod::calcCellCells
 //    }
 //
 //    // 2. For boundary faces is offsetted coupled neighbour
-//    forAll(patches, patchi)
+//    for (const polyPatch& pp : patches)
 //    {
-//        const polyPatch& pp = patches[patchi];
-//
 //        if (pp.coupled() && (parallel || !isA<processorPolyPatch>(pp)))
 //        {
 //            label facei = pp.start();
@@ -1147,8 +1128,8 @@ void Foam::decompositionMethod::calcCellCells
 //                        m[offsets[own] + nFacesPerCell[own]++] = globalNei;
 //                    }
 //
-//                    facei++;
-//                    bFacei++;
+//                    ++facei;
+//                    ++bFacei;
 //                }
 //            }
 //        }
@@ -1304,7 +1285,7 @@ Foam::labelList Foam::decompositionMethod::decompose
 
     //- Additional connections between boundary faces
     const List<labelPair>& explicitConnections
-)
+) const
 {
     // Any weights specified?
     label nWeights = returnReduce(cellWeights.size(), sumOp<label>());
@@ -1606,9 +1587,8 @@ Foam::labelList Foam::decompositionMethod::decompose
             syncTools::swapBoundaryCellList(mesh, finalDecomp, nbrDecomp);
 
             const polyBoundaryMesh& patches = mesh.boundaryMesh();
-            forAll(patches, patchi)
+            for (const polyPatch& pp : patches)
             {
-                const polyPatch& pp = patches[patchi];
                 if (pp.coupled())
                 {
                     forAll(pp, i)
@@ -1649,7 +1629,7 @@ void Foam::decompositionMethod::setConstraints
     PtrList<labelList>& specifiedProcessorFaces,
     labelList& specifiedProcessor,
     List<labelPair>& explicitConnections
-)
+) const
 {
     blockedFace.setSize(mesh.nFaces());
     blockedFace = true;
@@ -1657,9 +1637,9 @@ void Foam::decompositionMethod::setConstraints
     specifiedProcessorFaces.clear();
     explicitConnections.clear();
 
-    forAll(constraints_, constrainti)
+    for (const decompositionConstraint& decompConstraint : constraints_)
     {
-        constraints_[constrainti].add
+        decompConstraint.add
         (
             mesh,
             blockedFace,
@@ -1679,11 +1659,11 @@ void Foam::decompositionMethod::applyConstraints
     const labelList& specifiedProcessor,
     const List<labelPair>& explicitConnections,
     labelList& decomposition
-)
+) const
 {
-    forAll(constraints_, constrainti)
+    for (const decompositionConstraint& decompConstraint : constraints_)
     {
-        constraints_[constrainti].apply
+        decompConstraint.apply
         (
             mesh,
             blockedFace,
@@ -1700,7 +1680,7 @@ Foam::labelList Foam::decompositionMethod::decompose
 (
     const polyMesh& mesh,
     const scalarField& cellWeights
-)
+) const
 {
     // Collect all constraints
 
diff --git a/src/parallel/decompose/decompositionMethods/decompositionMethod/decompositionMethod.H b/src/parallel/decompose/decompositionMethods/decompositionMethod/decompositionMethod.H
index 96ad3afc98..4c4aad8994 100644
--- a/src/parallel/decompose/decompositionMethods/decompositionMethod/decompositionMethod.H
+++ b/src/parallel/decompose/decompositionMethods/decompositionMethod/decompositionMethod.H
@@ -3,7 +3,7 @@
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     |
     \\  /    A nd           | Copyright (C) 2011-2016 OpenFOAM Foundation
-     \\/     M anipulation  | Copyright (C) 2015-2017 OpenCFD Ltd.
+     \\/     M anipulation  | Copyright (C) 2015-2018 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -53,8 +53,10 @@ class decompositionMethod
         //- Set PtrList of constraints by reading decompositionDict_.
         void readConstraints();
 
-        //- Disallow default bitwise copy construct and assignment
+        //- No copy construct
         decompositionMethod(const decompositionMethod&) = delete;
+
+        //- No copy assignment
         void operator=(const decompositionMethod&) = delete;
 
 
@@ -210,8 +212,7 @@ public:
 
 
     //- Destructor
-    virtual ~decompositionMethod()
-    {}
+    virtual ~decompositionMethod() = default;
 
 
     // Member Functions
@@ -222,187 +223,192 @@ public:
             return nDomains_;
         }
 
-        //- Is method parallel aware (i.e. does it synchronize domains across
-        //  proc boundaries)
+        //- Is method parallel aware?
+        //  (i.e. does it synchronize domains across proc boundaries)
         virtual bool parallelAware() const = 0;
 
 
-        // No topology (implemented by geometric decomposers)
+    // No topology (implemented by geometric decomposers)
 
-            //- Return for every coordinate the wanted processor number.
-            virtual labelList decompose
-            (
-                const pointField& points,
-                const scalarField& pointWeights
-            )
-            {
-                NotImplemented;
-                return labelList(0);
-            }
+        //- Return for every coordinate the wanted processor number.
+        virtual labelList decompose
+        (
+            const pointField& points,
+            const scalarField& pointWeights
+        ) const
+        {
+            NotImplemented;
+            return labelList(0);
+        }
 
-            //- Like decompose but with uniform weights on the points
-            virtual labelList decompose(const pointField&)
-            {
-                NotImplemented;
-                return labelList(0);
-            }
+        //- Decompose with uniform weights on the points
+        virtual labelList decompose(const pointField& points) const
+        {
+            NotImplemented;
+            return labelList(0);
+        }
 
 
-        // Topology provided by mesh
+    // Topology provided by mesh
 
-            //- Return for every coordinate the wanted processor number. Use the
-            //  mesh connectivity (if needed)
-            virtual labelList decompose
-            (
-                const polyMesh& mesh,
-                const pointField& points,
-                const scalarField& pointWeights
-            ) = 0;
+        //- Return for every coordinate the wanted processor number.
+        //  Use the mesh connectivity (if needed)
+        virtual labelList decompose
+        (
+            const polyMesh& mesh,
+            const pointField& points,
+            const scalarField& pointWeights
+        ) const = 0;
 
-            //- Like decompose but with uniform weights on the points
-            virtual labelList decompose(const polyMesh&, const pointField&);
+        //- Decompose with uniform weights on the points
+        virtual labelList decompose
+        (
+            const polyMesh& mesh,
+            const pointField& points
+        ) const;
 
 
-            //- Return for every coordinate the wanted processor number. Gets
-            //  passed agglomeration map (from fine to coarse cells) and coarse
-            //  cell
-            //  location. Can be overridden by decomposers that provide this
-            //  functionality natively. Coarse cells are local to the processor
-            //  (if in parallel). If you want to have coarse cells spanning
-            //  processors use the globalCellCells instead.
-            virtual labelList decompose
-            (
-                const polyMesh& mesh,
-                const labelList& cellToRegion,
-                const pointField& regionPoints,
-                const scalarField& regionWeights
-            );
+        //- Return for every coordinate the wanted processor number. Gets
+        //  passed agglomeration map (from fine to coarse cells) and coarse
+        //  cell
+        //  location. Can be overridden by decomposers that provide this
+        //  functionality natively. Coarse cells are local to the processor
+        //  (if in parallel). If you want to have coarse cells spanning
+        //  processors use the globalCellCells instead.
+        virtual labelList decompose
+        (
+            const polyMesh& mesh,
+            const labelList& cellToRegion,
+            const pointField& regionPoints,
+            const scalarField& regionWeights
+        ) const;
 
-            //- Like decompose but with uniform weights on the regions
-            virtual labelList decompose
-            (
-                const polyMesh& mesh,
-                const labelList& cellToRegion,
-                const pointField& regionPoints
-            );
+        //- Like decompose but with uniform weights on the regions
+        virtual labelList decompose
+        (
+            const polyMesh& mesh,
+            const labelList& cellToRegion,
+            const pointField& regionPoints
+        ) const;
 
 
-        // Topology provided explicitly addressing
+    // Topology provided explicitly addressing
 
-            //- Return for every coordinate the wanted processor number.
-            //  The connectivity is equal to mesh.cellCells() except for
-            //  - in parallel the cell numbers are global cell numbers
-            //    (starting
-            //    from 0 at processor0 and then incrementing all through the
-            //    processors)
-            //  - the connections are across coupled patches
-            virtual labelList decompose
-            (
-                const labelListList& globalCellCells,
-                const pointField& cc,
-                const scalarField& cWeights
-            ) = 0;
+        //- Return for every coordinate the wanted processor number.
+        //  The connectivity is equal to mesh.cellCells() except for
+        //  - in parallel the cell numbers are global cell numbers
+        //    (starting
+        //    from 0 at processor0 and then incrementing all through the
+        //    processors)
+        //  - the connections are across coupled patches
+        virtual labelList decompose
+        (
+            const labelListList& globalCellCells,
+            const pointField& cc,
+            const scalarField& cWeights
+        ) const = 0;
 
-            //- Like decompose but with uniform weights on the cells
-            virtual labelList decompose
-            (
-                const labelListList& globalCellCells,
-                const pointField& cc
-            );
+        //- Like decompose but with uniform weights on the cells
+        virtual labelList decompose
+        (
+            const labelListList& globalCellCells,
+            const pointField& cc
+        ) const;
 
 
-        // Other
+    // Other
 
-            //- Helper: determine (local or global) cellCells from mesh
-            //  agglomeration. Agglomeration is local to the processor.
-            //  local  : connections are in local indices. Coupled across
-            //           cyclics but not processor patches.
-            //  global : connections are in global indices. Coupled across
-            //            cyclics and processor patches.
-            static void calcCellCells
-            (
-                const polyMesh& mesh,
-                const labelList& agglom,
-                const label nLocalCoarse,
-                const bool global,
-                CompactListList<label>& cellCells
-            );
+        //- Helper: determine (local or global) cellCells from mesh
+        //  agglomeration. Agglomeration is local to the processor.
+        //  local  : connections are in local indices. Coupled across
+        //           cyclics but not processor patches.
+        //  global : connections are in global indices. Coupled across
+        //            cyclics and processor patches.
+        static void calcCellCells
+        (
+            const polyMesh& mesh,
+            const labelList& agglom,
+            const label nLocalCoarse,
+            const bool global,
+            CompactListList<label>& cellCells
+        );
 
-            //- Helper: determine (local or global) cellCells and face weights
-            //  from mesh agglomeration.
-            //  Uses mag of faceArea as weights
-            static void calcCellCells
-            (
-                const polyMesh& mesh,
-                const labelList& agglom,
-                const label nLocalCoarse,
-                const bool parallel,
-                CompactListList<label>& cellCells,
-                CompactListList<scalar>& cellCellWeights
-            );
+        //- Helper: determine (local or global) cellCells and face weights
+        //  from mesh agglomeration.
+        //  Uses mag of faceArea as weights
+        static void calcCellCells
+        (
+            const polyMesh& mesh,
+            const labelList& agglom,
+            const label nLocalCoarse,
+            const bool parallel,
+            CompactListList<label>& cellCells,
+            CompactListList<scalar>& cellCellWeights
+        );
 
-            //- Helper: extract constraints:
-            //  blockedface: existing faces where owner and neighbour on same
-            //               proc
-            //  explicitConnections: sets of boundary faces  ,,     ,,
-            //  specifiedProcessorFaces: groups of faces with all cells on
-            //  same processor.
-            void setConstraints
-            (
-                const polyMesh& mesh,
-                boolList& blockedFace,
-                PtrList<labelList>& specifiedProcessorFaces,
-                labelList& specifiedProcessor,
-                List<labelPair>& explicitConnections
-            );
+        //- Helper: extract constraints:
+        //  blockedface: existing faces where owner and neighbour on same
+        //               proc
+        //  explicitConnections: sets of boundary faces  ,,     ,,
+        //  specifiedProcessorFaces: groups of faces with all cells on
+        //  same processor.
+        void setConstraints
+        (
+            const polyMesh& mesh,
+            boolList& blockedFace,
+            PtrList<labelList>& specifiedProcessorFaces,
+            labelList& specifiedProcessor,
+            List<labelPair>& explicitConnections
+        ) const;
 
-            //- Helper: apply constraints to a decomposition. This gives
-            //  constraints opportunity to modify decomposition in case
-            //  the native decomposition method has not obeyed all constraints
-            void applyConstraints
-            (
-                const polyMesh& mesh,
-                const boolList& blockedFace,
-                const PtrList<labelList>& specifiedProcessorFaces,
-                const labelList& specifiedProcessor,
-                const List<labelPair>& explicitConnections,
-                labelList& finalDecomp
-            );
+        //- Helper: apply constraints to a decomposition.
+        //  This gives constraints opportunity to modify decomposition in case
+        //  the native decomposition method has not obeyed all constraints
+        void applyConstraints
+        (
+            const polyMesh& mesh,
+            const boolList& blockedFace,
+            const PtrList<labelList>& specifiedProcessorFaces,
+            const labelList& specifiedProcessor,
+            const List<labelPair>& explicitConnections,
+            labelList& finalDecomp
+        ) const;
 
-            // Decompose a mesh with constraints:
-            // - blockedFace : whether owner and neighbour should be on same
-            //   processor
-            // - specifiedProcessorFaces, specifiedProcessor : sets of faces
-            //   that should go to same processor (as specified in
-            //   specifiedProcessor, can be -1)
-            // - explicitConnections : connections between baffle faces
-            //   (blockedFace should be false on these). Owner and
-            //   neighbour on same processor.
-            // Set all to zero size to have unconstrained decomposition.
-            virtual labelList decompose
-            (
-                const polyMesh& mesh,
-                const scalarField& cellWeights,
-                const boolList& blockedFace,
-                const PtrList<labelList>& specifiedProcessorFaces,
-                const labelList& specifiedProcessor,
-                const List<labelPair>& explicitConnections
-            );
+        // Decompose a mesh with constraints:
+        // - blockedFace : whether owner and neighbour should be on same
+        //   processor
+        // - specifiedProcessorFaces, specifiedProcessor : sets of faces
+        //   that should go to same processor (as specified in
+        //   specifiedProcessor, can be -1)
+        // - explicitConnections : connections between baffle faces
+        //   (blockedFace should be false on these). Owner and
+        //   neighbour on same processor.
+        // Set all to zero size to have unconstrained decomposition.
+        virtual labelList decompose
+        (
+            const polyMesh& mesh,
+            const scalarField& cellWeights,
+            const boolList& blockedFace,
+            const PtrList<labelList>& specifiedProcessorFaces,
+            const labelList& specifiedProcessor,
+            const List<labelPair>& explicitConnections
+        ) const;
 
 
-            //- Decompose a mesh. Apply all constraints from decomposeParDict
-            //  ('preserveFaceZones' etc). Calls either
-            //  - no constraints, empty weights:
-            //      decompose(mesh, cellCentres())
-            //  - no constraints, set weights:
-            //      decompose(mesh, cellCentres(), cellWeights)
-            //  - valid constraints:
-            //      decompose(mesh, cellToRegion, regionPoints, regionWeights)
-            labelList decompose
-            (
-                const polyMesh& mesh,
-                const scalarField& cWeights
-            );
+        //- Decompose a mesh.
+        //  Apply all constraints from decomposeParDict
+        //  ('preserveFaceZones' etc). Calls either
+        //  - no constraints, empty weights:
+        //      decompose(mesh, cellCentres())
+        //  - no constraints, set weights:
+        //      decompose(mesh, cellCentres(), cellWeights)
+        //  - valid constraints:
+        //      decompose(mesh, cellToRegion, regionPoints, regionWeights)
+        labelList decompose
+        (
+            const polyMesh& mesh,
+            const scalarField& cWeights
+        ) const;
 
 };
 
diff --git a/src/parallel/decompose/decompositionMethods/geomDecomp/geomDecomp.H b/src/parallel/decompose/decompositionMethods/geomDecomp/geomDecomp.H
index 7684a2ef4e..b334ef4323 100644
--- a/src/parallel/decompose/decompositionMethods/geomDecomp/geomDecomp.H
+++ b/src/parallel/decompose/decompositionMethods/geomDecomp/geomDecomp.H
@@ -3,7 +3,7 @@
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     |
     \\  /    A nd           | Copyright (C) 2011 OpenFOAM Foundation
-     \\/     M anipulation  |
+     \\/     M anipulation  | Copyright (C) 2018 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -99,15 +99,17 @@ public:
         );
 
 
+    // Member Functions
+
         //- Return for every coordinate the wanted processor number.
         virtual labelList decompose
         (
             const pointField& points,
             const scalarField& pointWeights
-        ) = 0;
+        ) const = 0;
 
-        //- Like decompose but with uniform weights on the points
-        virtual labelList decompose(const pointField&) = 0;
+        //- Decompose with uniform weights on the points
+        virtual labelList decompose(const pointField& points) const = 0;
 
 };
 
diff --git a/src/parallel/decompose/decompositionMethods/hierarchGeomDecomp/hierarchGeomDecomp.C b/src/parallel/decompose/decompositionMethods/hierarchGeomDecomp/hierarchGeomDecomp.C
index 8c3dc51e12..d56e3ae19e 100644
--- a/src/parallel/decompose/decompositionMethods/hierarchGeomDecomp/hierarchGeomDecomp.C
+++ b/src/parallel/decompose/decompositionMethods/hierarchGeomDecomp/hierarchGeomDecomp.C
@@ -3,7 +3,7 @@
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     |
     \\  /    A nd           | Copyright (C) 2011-2016 OpenFOAM Foundation
-     \\/     M anipulation  | Copyright (C) 2015-2017 OpenCFD Ltd.
+     \\/     M anipulation  | Copyright (C) 2015-2018 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -154,7 +154,7 @@ void Foam::hierarchGeomDecomp::calculateSortedWeightedSizes
     sortedWeightedSizes[0] = 0;
     forAll(current, i)
     {
-        label pointi = current[indices[i]];
+        const label pointi = current[indices[i]];
         sortedWeightedSizes[i + 1] = sortedWeightedSizes[i] + weights[pointi];
     }
     // Non-dimensionalise and multiply by size.
@@ -332,7 +332,7 @@ void Foam::hierarchGeomDecomp::sortComponent
     const direction componentIndex, // index in decompOrder_
     const label mult,               // multiplication factor for finalDecomp
     labelList& finalDecomp
-)
+) const
 {
     // Current component
     label compI = decompOrder_[componentIndex];
@@ -348,7 +348,7 @@ void Foam::hierarchGeomDecomp::sortComponent
 
     forAll(current, i)
     {
-        label pointi = current[i];
+        const label pointi = current[i];
 
         sortedCoord[i] = points[pointi][compI];
     }
@@ -514,7 +514,7 @@ void Foam::hierarchGeomDecomp::sortComponent
     const direction componentIndex, // index in decompOrder_
     const label mult,               // multiplication factor for finalDecomp
     labelList& finalDecomp
-)
+) const
 {
     // Current component
     label compI = decompOrder_[componentIndex];
@@ -688,10 +688,39 @@ void Foam::hierarchGeomDecomp::sortComponent
 }
 
 
+// * * * * * * * * * * * * * * * * Constructors  * * * * * * * * * * * * * * //
+
+Foam::hierarchGeomDecomp::hierarchGeomDecomp
+(
+    const dictionary& decompDict
+)
+:
+    geomDecomp(typeName, decompDict),
+    decompOrder_({0,1,2})
+{
+    setDecompOrder();
+}
+
+
+Foam::hierarchGeomDecomp::hierarchGeomDecomp
+(
+    const dictionary& decompDict,
+    const word& regionName
+)
+:
+    geomDecomp(typeName, decompDict, regionName),
+    decompOrder_({0,1,2})
+{
+    setDecompOrder();
+}
+
+
+// * * * * * * * * * * * * * * * Member Functions  * * * * * * * * * * * * * //
+
 Foam::labelList Foam::hierarchGeomDecomp::decompose
 (
     const pointField& points
-)
+) const
 {
     // construct a list for the final result
     labelList finalDecomp(points.size(), 0);
@@ -732,7 +761,7 @@ Foam::labelList Foam::hierarchGeomDecomp::decompose
 (
     const pointField& points,
     const scalarField& weights
-)
+) const
 {
     // construct a list for the final result
     labelList finalDecomp(points.size(), 0);
@@ -770,31 +799,4 @@ Foam::labelList Foam::hierarchGeomDecomp::decompose
 }
 
 
-// * * * * * * * * * * * * * * * * Constructors  * * * * * * * * * * * * * * //
-
-Foam::hierarchGeomDecomp::hierarchGeomDecomp
-(
-    const dictionary& decompDict
-)
-:
-    geomDecomp(typeName, decompDict),
-    decompOrder_({0,1,2})
-{
-    setDecompOrder();
-}
-
-
-Foam::hierarchGeomDecomp::hierarchGeomDecomp
-(
-    const dictionary& decompDict,
-    const word& regionName
-)
-:
-    geomDecomp(typeName, decompDict, regionName),
-    decompOrder_({0,1,2})
-{
-    setDecompOrder();
-}
-
-
 // ************************************************************************* //
diff --git a/src/parallel/decompose/decompositionMethods/hierarchGeomDecomp/hierarchGeomDecomp.H b/src/parallel/decompose/decompositionMethods/hierarchGeomDecomp/hierarchGeomDecomp.H
index 90005577e7..663d45c574 100644
--- a/src/parallel/decompose/decompositionMethods/hierarchGeomDecomp/hierarchGeomDecomp.H
+++ b/src/parallel/decompose/decompositionMethods/hierarchGeomDecomp/hierarchGeomDecomp.H
@@ -3,7 +3,7 @@
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     |
     \\  /    A nd           | Copyright (C) 2011-2015 OpenFOAM Foundation
-     \\/     M anipulation  | Copyright (C) 2017 OpenCFD Ltd.
+     \\/     M anipulation  | Copyright (C) 2017-2018 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -148,7 +148,7 @@ class hierarchGeomDecomp
             const direction componentIndex, // index in decompOrder_
             const label prevMult,           // multiplication factor
             labelList& finalDecomp          // overall decomposition
-        );
+        ) const;
 
         //- Recursively sort in x,y,z (or rather acc. to decompOrder_)
         //- Using weighted points.
@@ -161,12 +161,15 @@ class hierarchGeomDecomp
             const direction componentIndex, // index in decompOrder_
             const label prevMult,           // multiplication factor
             labelList& finalDecomp          // overall decomposition
-        );
+        ) const;
 
-        //- Disallow default bitwise copy construct and assignment
-        void operator=(const hierarchGeomDecomp&) = delete;
+
+        //- No copy construct
         hierarchGeomDecomp(const hierarchGeomDecomp&) = delete;
 
+        //- No copy assignment
+        void operator=(const hierarchGeomDecomp&) = delete;
+
 
 public:
 
@@ -188,13 +191,12 @@ public:
 
 
     //- Destructor
-    virtual ~hierarchGeomDecomp()
-    {}
+    virtual ~hierarchGeomDecomp() = default;
 
 
     // Member Functions
 
-        //- Hierarchgeom is aware of processor boundaries
+        //- Hierarchical is aware of processor boundaries
         virtual bool parallelAware() const
         {
             return true;
@@ -205,34 +207,40 @@ public:
         (
             const pointField&,
             const scalarField& weights
-        );
+        ) const;
 
-        //- Without weights. Code for weighted decomposition is a bit complex
+        //- Decompose with uniform weights.
+        //  Code for weighted decomposition is a bit complex,
         //  so kept separate for now.
-        virtual labelList decompose(const pointField&);
+        virtual labelList decompose(const pointField&) const;
 
 
-        //- Return for every coordinate the wanted processor number. Use the
-        //  mesh connectivity (if needed)
+        //- Return for every coordinate the wanted processor number.
+        //  Use the mesh connectivity (if needed).
         virtual labelList decompose
         (
             const polyMesh& mesh,
             const pointField& cc,
             const scalarField& cWeights
-        )
+        ) const
         {
             return decompose(cc, cWeights);
         }
 
-        //- Without weights. Code for weighted decomposition is a bit complex
+        //- Decompose with uniform weights.
+        //  Code for weighted decomposition is a bit complex,
         //  so kept separate for now.
-        virtual labelList decompose(const polyMesh& mesh, const pointField& cc)
+        virtual labelList decompose
+        (
+            const polyMesh& mesh,
+            const pointField& cc
+        ) const
         {
             return decompose(cc);
         }
 
-        //- Return for every coordinate the wanted processor number. Explicitly
-        //  provided connectivity - does not use mesh_.
+        //- Return for every coordinate the wanted processor number.
+        //  Explicitly provided connectivity - does not use mesh_.
         //  The connectivity is equal to mesh.cellCells() except for
         //  - in parallel the cell numbers are global cell numbers (starting
         //    from 0 at processor0 and then incrementing all through the
@@ -243,7 +251,7 @@ public:
             const labelListList& globalCellCells,
             const pointField& cc,
             const scalarField& cWeights
-        )
+        ) const
         {
             return decompose(cc, cWeights);
         }
@@ -252,7 +260,7 @@ public:
         (
             const labelListList& globalCellCells,
             const pointField& cc
-        )
+        ) const
         {
             return decompose(cc);
         }
diff --git a/src/parallel/decompose/decompositionMethods/manualDecomp/manualDecomp.C b/src/parallel/decompose/decompositionMethods/manualDecomp/manualDecomp.C
index 23cbd33e31..86c5cb656c 100644
--- a/src/parallel/decompose/decompositionMethods/manualDecomp/manualDecomp.C
+++ b/src/parallel/decompose/decompositionMethods/manualDecomp/manualDecomp.C
@@ -3,7 +3,7 @@
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     |
     \\  /    A nd           | Copyright (C) 2011-2017 OpenFOAM Foundation
-     \\/     M anipulation  | Copyright (C) 2017 OpenCFD Ltd.
+     \\/     M anipulation  | Copyright (C) 2017-2018 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -77,7 +77,7 @@ Foam::labelList Foam::manualDecomp::decompose
     const polyMesh& mesh,
     const pointField& points,
     const scalarField& pointWeights
-)
+) const
 {
     labelIOList finalDecomp
     (
@@ -92,7 +92,7 @@ Foam::labelList Foam::manualDecomp::decompose
         )
     );
 
-    // check if the final decomposition is OK
+    // Check if the final decomposition is OK
 
     if (finalDecomp.size() != points.size())
     {
diff --git a/src/parallel/decompose/decompositionMethods/manualDecomp/manualDecomp.H b/src/parallel/decompose/decompositionMethods/manualDecomp/manualDecomp.H
index ac97c4dbb3..21c0e2764d 100644
--- a/src/parallel/decompose/decompositionMethods/manualDecomp/manualDecomp.H
+++ b/src/parallel/decompose/decompositionMethods/manualDecomp/manualDecomp.H
@@ -3,7 +3,7 @@
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     |
     \\  /    A nd           | Copyright (C) 2011-2015 OpenFOAM Foundation
-     \\/     M anipulation  | Copyright (C) 2017 OpenCFD Ltd.
+     \\/     M anipulation  | Copyright (C) 2017-2018 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -61,10 +61,12 @@ class manualDecomp
 
     // Private Member Functions
 
-        //- Disallow default bitwise copy construct and assignment
-        void operator=(const manualDecomp&) = delete;
+        //- No copy construct
         manualDecomp(const manualDecomp&) = delete;
 
+        //- No copy assignment
+        void operator=(const manualDecomp&) = delete;
+
 
 public:
 
@@ -86,30 +88,29 @@ public:
 
 
     //- Destructor
-    virtual ~manualDecomp()
-    {}
+    virtual ~manualDecomp() = default;
 
 
     // Member Functions
 
-        //- Manual decompose does not care about proc boundaries - is all
-        //  up to the user.
+        //- Manual decompose does not care about proc boundaries.
+        //- Is all up to the user.
         virtual bool parallelAware() const
         {
             return true;
         }
 
-        //- Return for every coordinate the wanted processor number. Use the
-        //  mesh connectivity (if needed)
+        //- Return for every coordinate the wanted processor number.
+        //  Use the mesh connectivity (if needed)
         virtual labelList decompose
         (
             const polyMesh& mesh,
             const pointField& cc,
             const scalarField& cWeights
-        );
+        ) const;
 
-        //- Return for every coordinate the wanted processor number. Explicitly
-        //  provided connectivity - does not use mesh_.
+        //- Return for every coordinate the wanted processor number.
+        //  Explicitly provided connectivity - does not use mesh_.
         //  The connectivity is equal to mesh.cellCells() except for
         //  - in parallel the cell numbers are global cell numbers (starting
         //    from 0 at processor0 and then incrementing all through the
@@ -120,7 +121,7 @@ public:
             const labelListList& globalCellCells,
             const pointField& cc,
             const scalarField& cWeights
-        )
+        ) const
         {
             NotImplemented;
             return labelList(0);
diff --git a/src/parallel/decompose/decompositionMethods/metisLikeDecomp/metisLikeDecomp.C b/src/parallel/decompose/decompositionMethods/metisLikeDecomp/metisLikeDecomp.C
index 7c3b6bb7fe..df79e3067e 100644
--- a/src/parallel/decompose/decompositionMethods/metisLikeDecomp/metisLikeDecomp.C
+++ b/src/parallel/decompose/decompositionMethods/metisLikeDecomp/metisLikeDecomp.C
@@ -2,7 +2,7 @@
   =========                 |
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     |
-    \\  /    A nd           | Copyright (C) 2017 OpenCFD Ltd.
+    \\  /    A nd           | Copyright (C) 2017-2018 OpenCFD Ltd.
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
 License
@@ -35,7 +35,7 @@ Foam::label Foam::metisLikeDecomp::decomposeGeneral
     const labelUList& xadj,
     const UList<scalar>& cWeights,
     List<label>& decomp
-)
+) const
 {
     if (!Pstream::parRun())
     {
@@ -182,7 +182,7 @@ Foam::labelList Foam::metisLikeDecomp::decompose
     const polyMesh& mesh,
     const pointField& points,
     const scalarField& pointWeights
-)
+) const
 {
     if (points.size() != mesh.nCells())
     {
@@ -218,7 +218,7 @@ Foam::labelList Foam::metisLikeDecomp::decompose
     const labelList& agglom,
     const pointField& agglomPoints,
     const scalarField& agglomWeights
-)
+) const
 {
     if (agglom.size() != mesh.nCells())
     {
@@ -264,7 +264,7 @@ Foam::labelList Foam::metisLikeDecomp::decompose
     const labelListList& globalCellCells,
     const pointField& cellCentres,
     const scalarField& cellWeights
-)
+) const
 {
     if (cellCentres.size() != globalCellCells.size())
     {
diff --git a/src/parallel/decompose/decompositionMethods/metisLikeDecomp/metisLikeDecomp.H b/src/parallel/decompose/decompositionMethods/metisLikeDecomp/metisLikeDecomp.H
index 69af7acd3c..223f249250 100644
--- a/src/parallel/decompose/decompositionMethods/metisLikeDecomp/metisLikeDecomp.H
+++ b/src/parallel/decompose/decompositionMethods/metisLikeDecomp/metisLikeDecomp.H
@@ -2,7 +2,7 @@
   =========                 |
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     |
-    \\  /    A nd           | Copyright (C) 2017 OpenCFD Ltd.
+    \\  /    A nd           | Copyright (C) 2017-2018 OpenCFD Ltd.
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
 License
@@ -53,10 +53,12 @@ class metisLikeDecomp
 {
     // Private Member Functions
 
-        //- Disallow default bitwise copy construct and assignment
-        void operator=(const metisLikeDecomp&) = delete;
+        //- No copy construct
         metisLikeDecomp(const metisLikeDecomp&) = delete;
 
+        //- No copy assignment
+        void operator=(const metisLikeDecomp&) = delete;
+
 
 protected:
 
@@ -75,7 +77,7 @@ protected:
             const labelUList& xadj,
             const UList<scalar>& cellWeights,
             List<label>& decomp
-        );
+        ) const;
 
         //- Decomposition with metis-like parameters
         virtual label decomposeSerial
@@ -84,7 +86,7 @@ protected:
             const labelUList& xadj,
             const UList<scalar>& cellWeights,
             List<label>& decomp
-        ) = 0;
+        ) const = 0;
 
 public:
 
@@ -116,8 +118,7 @@ public:
 
 
     //- Destructor
-    virtual ~metisLikeDecomp()
-    {}
+    virtual ~metisLikeDecomp() = default;
 
 
     // Member Functions
@@ -135,7 +136,7 @@ public:
             const polyMesh& mesh,
             const pointField& points,
             const scalarField& pointWeights
-        );
+        ) const;
 
         //- Return for every coordinate the wanted processor number.
         //  Gets passed agglomeration map (from fine to coarse cells) and coarse
@@ -148,7 +149,7 @@ public:
             const labelList& agglom,
             const pointField& regionPoints,
             const scalarField& regionWeights
-        );
+        ) const;
 
         //- Return for every coordinate the wanted processor number.
         //  Explicitly provided mesh connectivity.
@@ -163,7 +164,7 @@ public:
             const labelListList& globalCellCells,
             const pointField& cellCentres,
             const scalarField& cellWeights
-        );
+        ) const;
 };
 
 
diff --git a/src/parallel/decompose/decompositionMethods/multiLevelDecomp/multiLevelDecomp.C b/src/parallel/decompose/decompositionMethods/multiLevelDecomp/multiLevelDecomp.C
index d4428874d5..728e782cbb 100644
--- a/src/parallel/decompose/decompositionMethods/multiLevelDecomp/multiLevelDecomp.C
+++ b/src/parallel/decompose/decompositionMethods/multiLevelDecomp/multiLevelDecomp.C
@@ -3,7 +3,7 @@
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     |
     \\  /    A nd           | Copyright (C) 2011-2017 OpenFOAM Foundation
-     \\/     M anipulation  | Copyright (C) 2017 OpenCFD Ltd.
+     \\/     M anipulation  | Copyright (C) 2017-2018 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -330,7 +330,7 @@ void Foam::multiLevelDecomp::decompose
     const label leafOffset,
 
     labelList& finalDecomp
-)
+) const
 {
     labelList dist
     (
@@ -611,9 +611,9 @@ Foam::multiLevelDecomp::multiLevelDecomp
 
 bool Foam::multiLevelDecomp::parallelAware() const
 {
-    forAll(methods_, i)
+    for (const decompositionMethod& meth : methods_)
     {
-        if (!methods_[i].parallelAware())
+        if (!meth.parallelAware())
         {
             return false;
         }
@@ -628,7 +628,7 @@ Foam::labelList Foam::multiLevelDecomp::decompose
     const polyMesh& mesh,
     const pointField& cc,
     const scalarField& cWeights
-)
+) const
 {
     CompactListList<label> cellCells;
     calcCellCells(mesh, identity(cc.size()), cc.size(), true, cellCells);
@@ -657,7 +657,7 @@ Foam::labelList Foam::multiLevelDecomp::decompose
     const labelListList& globalPointPoints,
     const pointField& points,
     const scalarField& pointWeights
-)
+) const
 {
     labelList finalDecomp(points.size(), 0);
     labelList pointMap(identity(points.size()));
diff --git a/src/parallel/decompose/decompositionMethods/multiLevelDecomp/multiLevelDecomp.H b/src/parallel/decompose/decompositionMethods/multiLevelDecomp/multiLevelDecomp.H
index dcc40cd8da..bd0fa92b9f 100644
--- a/src/parallel/decompose/decompositionMethods/multiLevelDecomp/multiLevelDecomp.H
+++ b/src/parallel/decompose/decompositionMethods/multiLevelDecomp/multiLevelDecomp.H
@@ -3,7 +3,7 @@
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     |
     \\  /    A nd           | Copyright (C) 2011-2015 OpenFOAM Foundation
-     \\/     M anipulation  | Copyright (C) 2017 OpenCFD Ltd.
+     \\/     M anipulation  | Copyright (C) 2017-2018 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -93,12 +93,15 @@ class multiLevelDecomp
             const label leafOffset,
 
             labelList& finalDecomp
-        );
+        ) const;
 
-        //- Disallow default bitwise copy construct and assignment
-        void operator=(const multiLevelDecomp&) = delete;
+
+        //- No copy construct
         multiLevelDecomp(const multiLevelDecomp&) = delete;
 
+        //- No copy assignment
+        void operator=(const multiLevelDecomp&) = delete;
+
 
 public:
 
@@ -120,36 +123,35 @@ public:
 
 
     //- Destructor
-    virtual ~multiLevelDecomp()
-    {}
+    virtual ~multiLevelDecomp() = default;
 
 
     // Member Functions
 
-        //- Is method parallel aware (i.e. does it synchronize domains across
-        //  proc boundaries)
+        //- Is method parallel aware?
+        //  i.e. does it synchronize domains across proc boundaries
         virtual bool parallelAware() const;
 
         //- Inherit decompose from decompositionMethod
         using decompositionMethod::decompose;
 
-        //- Return for every coordinate the wanted processor number. Use the
-        //  mesh connectivity (if needed)
+        //- Return for every coordinate the wanted processor number.
+        //  Use the mesh connectivity (if needed)
         virtual labelList decompose
         (
             const polyMesh& mesh,
             const pointField& points,
             const scalarField& pointWeights
-        );
+        ) const;
 
-        //- Return for every coordinate the wanted processor number. Explicitly
-        //  provided connectivity - does not use mesh_.
+        //- Return for every coordinate the wanted processor number.
+        //  Explicitly provided connectivity - does not use mesh_.
         virtual labelList decompose
         (
             const labelListList& globalCellCells,
             const pointField& cc,
             const scalarField& cWeights
-        );
+        ) const;
 };
 
 
diff --git a/src/parallel/decompose/decompositionMethods/noDecomp/noDecomp.H b/src/parallel/decompose/decompositionMethods/noDecomp/noDecomp.H
index 74169998d2..78c5e49030 100644
--- a/src/parallel/decompose/decompositionMethods/noDecomp/noDecomp.H
+++ b/src/parallel/decompose/decompositionMethods/noDecomp/noDecomp.H
@@ -3,7 +3,7 @@
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     |
     \\  /    A nd           | Copyright (C) 2012-2015 OpenFOAM Foundation
-     \\/     M anipulation  | Copyright (C) 2017 OpenCFD Ltd.
+     \\/     M anipulation  | Copyright (C) 2017-2018 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -53,10 +53,12 @@ class noDecomp
 
     // Private Member Functions
 
-        //- Disallow default bitwise copy construct and assignment
-        void operator=(const noDecomp&) = delete;
+        //- No copy construct
         noDecomp(const noDecomp&) = delete;
 
+        //- No copy assignment
+        void operator=(const noDecomp&) = delete;
+
 
 public:
 
@@ -78,14 +80,12 @@ public:
 
 
     //- Destructor
-    virtual ~noDecomp()
-    {}
+    virtual ~noDecomp() = default;
 
 
     // Member Functions
 
-        //- Manual decompose does not care about proc boundaries - it is all
-        //- up to the user.
+        //- Does not care about proc boundaries, it is all up to the user.
         virtual bool parallelAware() const
         {
             return true;
@@ -98,7 +98,7 @@ public:
             const polyMesh& mesh,
             const pointField& cc,
             const scalarField& cWeights
-        )
+        ) const
         {
             return labelList(cc.size(), Pstream::myProcNo());
         }
@@ -115,7 +115,7 @@ public:
             const labelListList& globalCellCells,
             const pointField& cc,
             const scalarField& cWeights
-        )
+        ) const
         {
             return labelList(globalCellCells.size(), Pstream::myProcNo());
         }
diff --git a/src/parallel/decompose/decompositionMethods/simpleGeomDecomp/simpleGeomDecomp.C b/src/parallel/decompose/decompositionMethods/simpleGeomDecomp/simpleGeomDecomp.C
index ece25f250f..8782603cf7 100644
--- a/src/parallel/decompose/decompositionMethods/simpleGeomDecomp/simpleGeomDecomp.C
+++ b/src/parallel/decompose/decompositionMethods/simpleGeomDecomp/simpleGeomDecomp.C
@@ -3,7 +3,7 @@
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     |
     \\  /    A nd           | Copyright (C) 2011-2017 OpenFOAM Foundation
-     \\/     M anipulation  | Copyright (C) 2017 OpenCFD Ltd.
+     \\/     M anipulation  | Copyright (C) 2017-2018 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -63,7 +63,7 @@ void Foam::simpleGeomDecomp::assignToProcessorGroup
 (
     labelList& processorGroup,
     const label nProcGroup
-) const
+)
 {
     label jump = processorGroup.size()/nProcGroup;
     label jumpb = jump + 1;
@@ -100,7 +100,7 @@ void Foam::simpleGeomDecomp::assignToProcessorGroup
     const labelList& indices,
     const scalarField& weights,
     const scalar summedWeights
-) const
+)
 {
     // This routine gets the sorted points.
     // Easiest to explain with an example.
@@ -326,7 +326,7 @@ Foam::simpleGeomDecomp::simpleGeomDecomp
 Foam::labelList Foam::simpleGeomDecomp::decompose
 (
     const pointField& points
-)
+) const
 {
     if (!Pstream::parRun())
     {
@@ -347,7 +347,7 @@ Foam::labelList Foam::simpleGeomDecomp::decompose
             nTotalPoints += points.size();
 
             // Add slaves
-            for (int slave=1; slave<Pstream::nProcs(); slave++)
+            for (int slave=1; slave<Pstream::nProcs(); ++slave)
             {
                 IPstream fromSlave(Pstream::commsTypes::scheduled, slave);
                 pointField nbrPoints(fromSlave);
@@ -364,7 +364,7 @@ Foam::labelList Foam::simpleGeomDecomp::decompose
             labelList finalDecomp(decomposeOneProc(allPoints));
 
             // Send back
-            for (int slave=1; slave<Pstream::nProcs(); slave++)
+            for (int slave=1; slave<Pstream::nProcs(); ++slave)
             {
                 OPstream toSlave(Pstream::commsTypes::scheduled, slave);
                 toSlave << SubField<label>
@@ -409,7 +409,7 @@ Foam::labelList Foam::simpleGeomDecomp::decompose
 (
     const pointField& points,
     const scalarField& weights
-)
+) const
 {
     if (!Pstream::parRun())
     {
@@ -432,7 +432,7 @@ Foam::labelList Foam::simpleGeomDecomp::decompose
             nTotalPoints += points.size();
 
             // Add slaves
-            for (int slave=1; slave<Pstream::nProcs(); slave++)
+            for (int slave=1; slave<Pstream::nProcs(); ++slave)
             {
                 IPstream fromSlave(Pstream::commsTypes::scheduled, slave);
                 pointField nbrPoints(fromSlave);
@@ -456,7 +456,7 @@ Foam::labelList Foam::simpleGeomDecomp::decompose
             labelList finalDecomp(decomposeOneProc(allPoints, allWeights));
 
             // Send back
-            for (int slave=1; slave<Pstream::nProcs(); slave++)
+            for (int slave=1; slave<Pstream::nProcs(); ++slave)
             {
                 OPstream toSlave(Pstream::commsTypes::scheduled, slave);
                 toSlave << SubField<label>
diff --git a/src/parallel/decompose/decompositionMethods/simpleGeomDecomp/simpleGeomDecomp.H b/src/parallel/decompose/decompositionMethods/simpleGeomDecomp/simpleGeomDecomp.H
index c5abc336d9..b4e16411b5 100644
--- a/src/parallel/decompose/decompositionMethods/simpleGeomDecomp/simpleGeomDecomp.H
+++ b/src/parallel/decompose/decompositionMethods/simpleGeomDecomp/simpleGeomDecomp.H
@@ -3,7 +3,7 @@
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     |
     \\  /    A nd           | Copyright (C) 2011 OpenFOAM Foundation
-     \\/     M anipulation  |
+     \\/     M anipulation  | Copyright (C) 2018 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -57,16 +57,16 @@ class simpleGeomDecomp
 {
     // Private Member Functions
 
-        void assignToProcessorGroup(labelList&, const label) const;
+        static void assignToProcessorGroup(labelList&, const label);
 
-        void assignToProcessorGroup
+        static void assignToProcessorGroup
         (
             labelList& processorGroup,
             const label nProcGroup,
             const labelList& indices,
             const scalarField& weights,
             const scalar summedWeights
-        ) const;
+        );
 
         labelList decomposeOneProc(const pointField& points) const;
 
@@ -76,8 +76,11 @@ class simpleGeomDecomp
             const scalarField& weights
         ) const;
 
-        //- Disallow default bitwise copy construct and assignment
+
+        //- No copy construct
         void operator=(const simpleGeomDecomp&) = delete;
+
+        //- No copy assignment
         simpleGeomDecomp(const simpleGeomDecomp&) = delete;
 
 
@@ -101,36 +104,46 @@ public:
 
 
     //- Destructor
-    virtual ~simpleGeomDecomp()
-    {}
+    virtual ~simpleGeomDecomp() = default;
 
 
     // Member Functions
 
+        //- Simple sends all points to the master for decomposition.
         virtual bool parallelAware() const
         {
-            // simpleDecomp sends all points to the master which does
-            // the decomposition.
             return true;
         }
 
-        virtual labelList decompose(const pointField&);
+        //- Decompose with uniform weights.
+        virtual labelList decompose(const pointField& points) const;
 
-        virtual labelList decompose(const pointField&, const scalarField&);
+        //- Return for every coordinate the wanted processor number.
+        virtual labelList decompose
+        (
+            const pointField& points,
+            const scalarField& weights
+        ) const;
 
-        virtual labelList decompose(const polyMesh&, const pointField& points)
+        //- Decompose with uniform weights.
+        virtual labelList decompose
+        (
+            const polyMesh&,
+            const pointField& points
+        ) const
         {
             return decompose(points);
         }
 
+        //- Return for every coordinate the wanted processor number.
         virtual labelList decompose
         (
             const polyMesh&,
             const pointField& points,
-            const scalarField& pointWeights
-        )
+            const scalarField& weights
+        ) const
         {
-            return decompose(points, pointWeights);
+            return decompose(points, weights);
         }
 
         //- Explicitly provided connectivity
@@ -139,7 +152,7 @@ public:
             const labelListList& globalCellCells,
             const pointField& cc,
             const scalarField& cWeights
-        )
+        ) const
         {
             return decompose(cc, cWeights);
         }
diff --git a/src/parallel/decompose/decompositionMethods/structuredDecomp/structuredDecomp.C b/src/parallel/decompose/decompositionMethods/structuredDecomp/structuredDecomp.C
index a44e4b64a4..c7e1a89342 100644
--- a/src/parallel/decompose/decompositionMethods/structuredDecomp/structuredDecomp.C
+++ b/src/parallel/decompose/decompositionMethods/structuredDecomp/structuredDecomp.C
@@ -3,7 +3,7 @@
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     |
     \\  /    A nd           | Copyright (C) 2011-2017 OpenFOAM Foundation
-     \\/     M anipulation  |
+     \\/     M anipulation  | Copyright (C) 2018 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -70,7 +70,7 @@ Foam::labelList Foam::structuredDecomp::decompose
     const polyMesh& mesh,
     const pointField& cc,
     const scalarField& cWeights
-)
+) const
 {
     const polyBoundaryMesh& pbm = mesh.boundaryMesh();
     const labelHashSet patchIDs(pbm.patchSet(patches_));
@@ -165,14 +165,14 @@ Foam::labelList Foam::structuredDecomp::decompose
 
 Foam::labelList Foam::structuredDecomp::decompose
 (
-    const labelListList& globalPointPoints,
-    const pointField& points,
-    const scalarField& pointWeights
-)
+    const labelListList& globalCellCells,
+    const pointField& cc,
+    const scalarField& cWeights
+) const
 {
     NotImplemented;
 
-    return labelList::null();
+    return labelList(0);
 }
 
 
diff --git a/src/parallel/decompose/decompositionMethods/structuredDecomp/structuredDecomp.H b/src/parallel/decompose/decompositionMethods/structuredDecomp/structuredDecomp.H
index 3c742944b9..95d1246b74 100644
--- a/src/parallel/decompose/decompositionMethods/structuredDecomp/structuredDecomp.H
+++ b/src/parallel/decompose/decompositionMethods/structuredDecomp/structuredDecomp.H
@@ -3,7 +3,7 @@
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     |
     \\  /    A nd           | Copyright (C) 2011-2012 OpenFOAM Foundation
-     \\/     M anipulation  |
+     \\/     M anipulation  | Copyright (C) 2018 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -60,10 +60,12 @@ class structuredDecomp
 
     // Private Member Functions
 
-        //- Disallow default bitwise copy construct and assignment
-        void operator=(const structuredDecomp&) = delete;
+        //- No copy construct
         structuredDecomp(const structuredDecomp&) = delete;
 
+        //- No copy assignment
+        void operator=(const structuredDecomp&) = delete;
+
 
 public:
 
@@ -83,27 +85,27 @@ public:
 
     // Member Functions
 
-        //- Is method parallel aware (i.e. does it synchronize domains across
-        //  proc boundaries)
+        //- Is method parallel aware
+        //  (i.e. does it synchronize domains across proc boundaries)
         virtual bool parallelAware() const;
 
-        //- Return for every coordinate the wanted processor number. Use the
-        //  mesh connectivity (if needed)
+        //- Return for every coordinate the wanted processor number.
+        //  Use the mesh connectivity (if needed)
         virtual labelList decompose
         (
             const polyMesh& mesh,
             const pointField& points,
             const scalarField& pointWeights
-        );
+        ) const;
 
-        //- Return for every coordinate the wanted processor number. Explicitly
-        //  provided connectivity - does not use mesh_.
+        //- Return for every coordinate the wanted processor number.
+        //  Explicitly provided connectivity - does not use mesh_.
         virtual labelList decompose
         (
             const labelListList& globalCellCells,
             const pointField& cc,
             const scalarField& cWeights
-        );
+        ) const;
 };
 
 
diff --git a/src/parallel/decompose/kahipDecomp/kahipDecomp.C b/src/parallel/decompose/kahipDecomp/kahipDecomp.C
index 7774934163..6177e90a7f 100644
--- a/src/parallel/decompose/kahipDecomp/kahipDecomp.C
+++ b/src/parallel/decompose/kahipDecomp/kahipDecomp.C
@@ -2,7 +2,7 @@
   =========                 |
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     |
-    \\  /    A nd           | Copyright (C) 2017 OpenCFD Ltd.
+    \\  /    A nd           | Copyright (C) 2017-2018 OpenCFD Ltd.
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
 License
@@ -78,7 +78,7 @@ Foam::label Foam::kahipDecomp::decomposeSerial
     const labelUList& xadj,
     const UList<scalar>& cWeights,
     List<label>& decomp
-)
+) const
 {
     // Default setup
     enum configs kahipConfig = configs::FAST;
diff --git a/src/parallel/decompose/kahipDecomp/kahipDecomp.H b/src/parallel/decompose/kahipDecomp/kahipDecomp.H
index 7084836a16..8a57f145fd 100644
--- a/src/parallel/decompose/kahipDecomp/kahipDecomp.H
+++ b/src/parallel/decompose/kahipDecomp/kahipDecomp.H
@@ -2,7 +2,7 @@
   =========                 |
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     |
-    \\  /    A nd           | Copyright (C) 2017 OpenCFD Ltd.
+    \\  /    A nd           | Copyright (C) 2017-2018 OpenCFD Ltd.
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
 License
@@ -84,12 +84,15 @@ class kahipDecomp
             const labelUList& xadj,
             const UList<scalar>& cellWeights,
             List<label>& decomp
-        );
+        ) const;
 
-        //- Disallow default bitwise copy construct and assignment
-        void operator=(const kahipDecomp&) = delete;
+
+        //- No copy construct
         kahipDecomp(const kahipDecomp&) = delete;
 
+        //- No copy assignment
+        void operator=(const kahipDecomp&) = delete;
+
 
 public:
 
@@ -127,8 +130,7 @@ public:
 
 
     //- Destructor
-    virtual ~kahipDecomp()
-    {}
+    virtual ~kahipDecomp() = default;
 
 
     // Member Functions
diff --git a/src/parallel/decompose/metisDecomp/metisDecomp.C b/src/parallel/decompose/metisDecomp/metisDecomp.C
index d6a4f5ea98..43b16be9f6 100644
--- a/src/parallel/decompose/metisDecomp/metisDecomp.C
+++ b/src/parallel/decompose/metisDecomp/metisDecomp.C
@@ -3,7 +3,7 @@
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     |
     \\  /    A nd           | Copyright (C) 2011-2016 OpenFOAM Foundation
-     \\/     M anipulation  | Copyright (C) 2016-2017 OpenCFD Ltd.
+     \\/     M anipulation  | Copyright (C) 2016-2018 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -64,7 +64,7 @@ Foam::label Foam::metisDecomp::decomposeSerial
     const labelUList& xadj,
     const UList<scalar>& cWeights,
     List<label>& decomp
-)
+) const
 {
     // Method of decomposition
     // recursive: multi-level recursive bisection (default)
diff --git a/src/parallel/decompose/metisDecomp/metisDecomp.H b/src/parallel/decompose/metisDecomp/metisDecomp.H
index 65e8f75182..b66ea4fbc5 100644
--- a/src/parallel/decompose/metisDecomp/metisDecomp.H
+++ b/src/parallel/decompose/metisDecomp/metisDecomp.H
@@ -3,7 +3,7 @@
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     |
     \\  /    A nd           | Copyright (C) 2011-2015 OpenFOAM Foundation
-     \\/     M anipulation  | Copyright (C) 2017 OpenCFD Ltd.
+     \\/     M anipulation  | Copyright (C) 2017-2018 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -83,12 +83,16 @@ class metisDecomp
             const labelUList& xadj,
             const UList<scalar>& cellWeights,
             List<label>& decomp
-        );
+        ) const;
 
-        //- Disallow default bitwise copy construct and assignment
-        void operator=(const metisDecomp&) = delete;
+
+        //- No copy construct
         metisDecomp(const metisDecomp&) = delete;
 
+        //- No copy assignment
+        void operator=(const metisDecomp&) = delete;
+
+
 
 public:
 
@@ -110,8 +114,7 @@ public:
 
 
     //- Destructor
-    virtual ~metisDecomp()
-    {}
+    virtual ~metisDecomp() = default;
 
 
     // Member Functions
diff --git a/src/parallel/decompose/ptscotchDecomp/ptscotchDecomp.C b/src/parallel/decompose/ptscotchDecomp/ptscotchDecomp.C
index 08a146053e..f5c12994c7 100644
--- a/src/parallel/decompose/ptscotchDecomp/ptscotchDecomp.C
+++ b/src/parallel/decompose/ptscotchDecomp/ptscotchDecomp.C
@@ -3,7 +3,7 @@
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     |
     \\  /    A nd           | Copyright (C) 2011-2017 OpenFOAM Foundation
-     \\/     M anipulation  | Copyright (C) 2015-2017 OpenCFD Ltd.
+     \\/     M anipulation  | Copyright (C) 2015-2018 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -213,7 +213,7 @@ License
 #include <mpi.h>
 #include "ptscotch.h"
 
-// Hack: scotch generates floating point errors so need to switch of error
+// Hack: scotch generates floating point errors so need to switch off error
 //       trapping!
 #ifdef __GLIBC__
     #ifndef _GNU_SOURCE
@@ -244,9 +244,10 @@ namespace Foam
     );
 }
 
+
 // * * * * * * * * * * * * * Private Member Functions  * * * * * * * * * * * //
 
-void Foam::ptscotchDecomp::graphPath(const polyMesh& mesh)
+void Foam::ptscotchDecomp::graphPath(const polyMesh& mesh) const
 {
     graphPath_ = mesh.time().path()/mesh.name();
 }
@@ -460,8 +461,8 @@ Foam::label Foam::ptscotchDecomp::decompose
     List<label>& finalDecomp
 ) const
 {
-    List<label> dummyAdjncy { 0 };
-    List<label> dummyXadj { 0 };
+    List<label> dummyAdjncy;
+    List<label> dummyXadj;
 
     return decompose
     (
@@ -822,7 +823,7 @@ Foam::labelList Foam::ptscotchDecomp::decompose
     const polyMesh& mesh,
     const pointField& points,
     const scalarField& pointWeights
-)
+) const
 {
     // Where to write graph
     graphPath(mesh);
@@ -873,7 +874,7 @@ Foam::labelList Foam::ptscotchDecomp::decompose
     const labelList& agglom,
     const pointField& agglomPoints,
     const scalarField& pointWeights
-)
+) const
 {
     // Where to write graph
     graphPath(mesh);
@@ -927,7 +928,7 @@ Foam::labelList Foam::ptscotchDecomp::decompose
     const labelListList& globalCellCells,
     const pointField& cellCentres,
     const scalarField& cWeights
-)
+) const
 {
     // Where to write graph
     graphPath_ = "ptscotch";
diff --git a/src/parallel/decompose/ptscotchDecomp/ptscotchDecomp.H b/src/parallel/decompose/ptscotchDecomp/ptscotchDecomp.H
index 9d613cd928..07f24c0717 100644
--- a/src/parallel/decompose/ptscotchDecomp/ptscotchDecomp.H
+++ b/src/parallel/decompose/ptscotchDecomp/ptscotchDecomp.H
@@ -3,7 +3,7 @@
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     |
     \\  /    A nd           | Copyright (C) 2011-2016 OpenFOAM Foundation
-     \\/     M anipulation  |
+     \\/     M anipulation  | Copyright (C) 2018 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -73,13 +73,13 @@ class ptscotchDecomp
         dictionary coeffsDict_;
 
         //- Output path and name for optional grf file.
-        fileName graphPath_;
+        mutable fileName graphPath_;
 
 
     // Private Member Functions
 
-        //- Set graph path and name
-        void graphPath(const polyMesh& mesh);
+        //- Set graph path and name (mutable)
+        void graphPath(const polyMesh& mesh) const;
 
         //- Check and print error message
         static void check(const int, const char*);
@@ -104,10 +104,13 @@ class ptscotchDecomp
             List<label>& finalDecomp
         ) const;
 
-        //- Disallow default bitwise copy construct and assignment
-        void operator=(const ptscotchDecomp&) = delete;
+
+        //- No copy construct
         ptscotchDecomp(const ptscotchDecomp&) = delete;
 
+        //- No copy assignment
+        void operator=(const ptscotchDecomp&) = delete;
+
 
 public:
 
@@ -126,33 +129,33 @@ public:
 
 
     //- Destructor
-    virtual ~ptscotchDecomp()
-    {}
+    virtual ~ptscotchDecomp() = default;
 
 
     // Member Functions
 
         virtual bool parallelAware() const
         {
-            // ptscotch does not know about proc boundaries
             return true;
         }
 
         //- Inherit decompose from decompositionMethod
         using decompositionMethod::decompose;
 
-        //- Return for every coordinate the wanted processor number. Use the
-        //  mesh connectivity (if needed). See note on weights in scotchDecomp.H
+        //- Return for every coordinate the wanted processor number.
+        //  Use the mesh connectivity (if needed).
+        //  See note on weights in scotchDecomp.H
         virtual labelList decompose
         (
             const polyMesh& mesh,
             const pointField& points,
             const scalarField& pointWeights
-        );
+        ) const;
 
-        //- Return for every coordinate the wanted processor number. Gets
-        //  passed agglomeration map (from fine to coarse cells) and coarse cell
-        //  location. Can be overridden by decomposers that provide this
+        //- Return for every coordinate the wanted processor number.
+        //  Gets passed agglomeration map (from fine to coarse cells) and
+        //  coarse cell location.
+        //  Can be overridden by decomposers that provide this
         //  functionality natively. See note on weights in scotchDecomp.H
         virtual labelList decompose
         (
@@ -160,10 +163,10 @@ public:
             const labelList& agglom,
             const pointField& regionPoints,
             const scalarField& regionWeights
-        );
+        ) const;
 
-        //- Return for every coordinate the wanted processor number. Explicitly
-        //  provided mesh connectivity.
+        //- Return for every coordinate the wanted processor number.
+        //  Explicitly provided mesh connectivity.
         //  The connectivity is equal to mesh.cellCells() except for
         //  - in parallel the cell numbers are global cell numbers (starting
         //    from 0 at processor0 and then incrementing all through the
@@ -175,7 +178,7 @@ public:
             const labelListList& globalCellCells,
             const pointField& cc,
             const scalarField& cWeights
-        );
+        ) const;
 
 };
 
diff --git a/src/parallel/decompose/scotchDecomp/scotchDecomp.C b/src/parallel/decompose/scotchDecomp/scotchDecomp.C
index a29ecc63f7..77067cdce1 100644
--- a/src/parallel/decompose/scotchDecomp/scotchDecomp.C
+++ b/src/parallel/decompose/scotchDecomp/scotchDecomp.C
@@ -3,7 +3,7 @@
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     |
     \\  /    A nd           | Copyright (C) 2011-2017 OpenFOAM Foundation
-     \\/     M anipulation  | Copyright (C) 2015-2017 OpenCFD Ltd.
+     \\/     M anipulation  | Copyright (C) 2015-2018 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -166,7 +166,7 @@ namespace Foam
 
 // * * * * * * * * * * * * * Private Member Functions  * * * * * * * * * * * //
 
-void Foam::scotchDecomp::graphPath(const polyMesh& mesh)
+void Foam::scotchDecomp::graphPath(const polyMesh& mesh) const
 {
     graphPath_ = mesh.time().path()/mesh.name() + ".grf";
 }
@@ -189,7 +189,7 @@ Foam::label Foam::scotchDecomp::decomposeSerial
     const labelUList& xadj,
     const UList<scalar>& cWeights,
     List<label>& decomp
-)
+) const
 {
     // Dump graph
     if (coeffsDict_.lookupOrDefault("writeGraph", false))
@@ -476,7 +476,7 @@ Foam::labelList Foam::scotchDecomp::decompose
     const polyMesh& mesh,
     const pointField& points,
     const scalarField& pointWeights
-)
+) const
 {
     // Where to write graph
     graphPath(mesh);
@@ -496,7 +496,7 @@ Foam::labelList Foam::scotchDecomp::decompose
     const labelList& agglom,
     const pointField& agglomPoints,
     const scalarField& pointWeights
-)
+) const
 {
     // Where to write graph
     graphPath(mesh);
@@ -516,7 +516,7 @@ Foam::labelList Foam::scotchDecomp::decompose
     const labelListList& globalCellCells,
     const pointField& cellCentres,
     const scalarField& cWeights
-)
+) const
 {
     // Where to write graph
     graphPath_ = "scotch.grf";
diff --git a/src/parallel/decompose/scotchDecomp/scotchDecomp.H b/src/parallel/decompose/scotchDecomp/scotchDecomp.H
index a32a682f30..6149fa8d7d 100644
--- a/src/parallel/decompose/scotchDecomp/scotchDecomp.H
+++ b/src/parallel/decompose/scotchDecomp/scotchDecomp.H
@@ -3,7 +3,7 @@
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     |
     \\  /    A nd           | Copyright (C) 2011-2016 OpenFOAM Foundation
-     \\/     M anipulation  | Copyright (C) 2017 OpenCFD Ltd.
+     \\/     M anipulation  | Copyright (C) 2017-2018 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -232,13 +232,13 @@ class scotchDecomp
     // Private data
 
         //- Output path and name for optional grf file.
-        fileName graphPath_;
+        mutable fileName graphPath_;
 
 
     // Private Member Functions
 
-        //- Set graph path and name
-        void graphPath(const polyMesh& mesh);
+        //- Set graph path and name (mutable)
+        void graphPath(const polyMesh& mesh) const;
 
         //- Check and print error message
         static void check(const int, const char*);
@@ -250,12 +250,15 @@ class scotchDecomp
             const labelUList& xadj,
             const UList<scalar>& cWeights,
             List<label>& decomp
-        );
+        ) const;
 
-        //- Disallow default bitwise copy construct and assignment
-        void operator=(const scotchDecomp&) = delete;
+
+        //- No copy construct
         scotchDecomp(const scotchDecomp&) = delete;
 
+        //- No copy assignment
+        void operator=(const scotchDecomp&) = delete;
+
 
 public:
 
@@ -277,15 +280,14 @@ public:
 
 
     //- Destructor
-    virtual ~scotchDecomp()
-    {}
+    virtual ~scotchDecomp() = default;
 
 
     // Member Functions
 
+        //- Knows about coupled boundaries
         virtual bool parallelAware() const
         {
-            // Knows about coupled boundaries
             return true;
         }
 
@@ -298,7 +300,7 @@ public:
             const polyMesh& mesh,
             const pointField& points,
             const scalarField& pointWeights
-        );
+        ) const;
 
         //- Return for every coordinate the wanted processor number.
         virtual labelList decompose
@@ -307,7 +309,7 @@ public:
             const labelList& agglom,
             const pointField& regionPoints,
             const scalarField& regionWeights
-        );
+        ) const;
 
         //- Return for every coordinate the wanted processor number.
         virtual labelList decompose
@@ -315,7 +317,7 @@ public:
             const labelListList& globalCellCells,
             const pointField& cc,
             const scalarField& cWeights
-        );
+        ) const;
 };