ENH: add global identity cartesian and cylindrical systems (#863)

src/meshTools/coordinate/systems/cartesianCS.C

@@ -2,7 +2,7 @@
   =========                 |
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     |
-    \\  /    A nd           | Copyright (C) 2018 OpenCFD Ltd.
+    \\  /    A nd           | Copyright (C) 2018-2019 OpenCFD Ltd.
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
                             | Copyright (C) 2011-2014 OpenFOAM Foundation
@@ -40,6 +40,9 @@ namespace coordSystem
 }
 
 
+const Foam::coordSystem::cartesian Foam::coordSystem::cartesian::null;
+
+
 // * * * * * * * * * * * * * * * * Constructors  * * * * * * * * * * * * * * //
 
 Foam::coordSystem::cartesian::cartesian()

src/meshTools/coordinate/systems/cartesianCS.H

@@ -2,7 +2,7 @@
   =========                 |
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     |
-    \\  /    A nd           | Copyright (C) 2018 OpenCFD Ltd.
+    \\  /    A nd           | Copyright (C) 2018-2019 OpenCFD Ltd.
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
                             | Copyright (C) 2011-2013 OpenFOAM Foundation
@@ -66,6 +66,12 @@ public:
     TypeNameNoDebug("cartesian");
 
 
+    // Static Members
+
+        //- Global (identity) cartesian coordinate system
+        static const cartesian null;
+
+
     // Constructors
 
         //- Construct null. This is an identity coordinateSystem.

src/meshTools/coordinate/systems/cylindricalCS.C

@@ -2,7 +2,7 @@
   =========                 |
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     |
-    \\  /    A nd           | Copyright (C) 2018 OpenCFD Ltd.
+    \\  /    A nd           | Copyright (C) 2018-2019 OpenCFD Ltd.
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
                             | Copyright (C) 2011-2016 OpenFOAM Foundation
@@ -41,6 +41,9 @@ namespace coordSystem
 }
 
 
+const Foam::coordSystem::cylindrical Foam::coordSystem::cylindrical::null;
+
+
 // * * * * * * * * * * * * * * * Local Functions * * * * * * * * * * * * * * //
 
 namespace Foam

src/meshTools/coordinate/systems/cylindricalCS.H

@@ -105,6 +105,12 @@ public:
     TypeNameNoDebug("cylindrical");
 
 
+    // Static Members
+
+        //- Global (identity) cylindrical coordinate system
+        static const cylindrical null;
+
+
     // Constructors
 
         //- Construct null (identity coordinateSystem)