ENH: new continuityError function object

Example usage:

    continuityError1
    {
        type        continuityError;
        libs        ("libfieldFunctionObjects.so");
        ...
        writeToFile yes;
        log         yes;
        phi         phi;
    }

src/functionObjects/field/continuityError/continuityError.H

@@ -0,0 +1,162 @@
+/*---------------------------------------------------------------------------*\
+  =========                 |
+  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
+   \\    /   O peration     |
+    \\  /    A nd           | Copyright (C) 2019 OpenCFD Ltd.
+     \\/     M anipulation  |
+-------------------------------------------------------------------------------
+License
+    This file is part of OpenFOAM.
+
+    OpenFOAM is free software: you can redistribute it and/or modify it
+    under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    OpenFOAM is distributed in the hope that it will be useful, but WITHOUT
+    ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+    FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+    for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with OpenFOAM.  If not, see <http://www.gnu.org/licenses/>.
+
+Class
+    Foam::functionObjects::continuityError
+
+Group
+    grpFieldFunctionObjects
+
+Description
+    Calculates the continuity error for a flux field
+
+Usage
+    Example of function object specification:
+    \verbatim
+    continuityError1
+    {
+        type        continuityError;
+        libs        ("libfieldFunctionObjects.so");
+        ...
+        writeToFile yes;
+        log         yes;
+        phi         phi;
+    }
+    \endverbatim
+
+    Where the entries comprise:
+    \table
+        Property     | Description             | Required    | Default value
+        type         | type name: continuityError  | yes         |
+        writeToFile  | write min/max data to file | no       | yes
+        log          | write min/max data to standard output | no | yes
+        phi          | name of flux field      | no | phi
+    \endtable
+
+    Output data is written to the file \<timeDir\>/continuityError.dat
+
+See also
+    Foam::functionObjects::fvMeshFunctionObject
+    Foam::functionObjects::writeFile
+
+SourceFiles
+    continuityError.C
+    continuityErrorTemplates.C
+
+\*---------------------------------------------------------------------------*/
+
+#ifndef functionObjects_continuityError_H
+#define functionObjects_continuityError_H
+
+#include "Switch.H"
+#include "fvMeshFunctionObject.H"
+#include "writeFile.H"
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+namespace Foam
+{
+namespace functionObjects
+{
+
+/*---------------------------------------------------------------------------*\
+                         Class continuityError Declaration
+\*---------------------------------------------------------------------------*/
+
+class continuityError
+:
+    public fvMeshFunctionObject,
+    public writeFile
+{
+private:
+
+    // Private Member Functions
+
+        //- No copy construct
+        continuityError(const continuityError&) = delete;
+
+        //- No copy assignment
+        void operator=(const continuityError&) = delete;
+
+
+protected:
+
+    // Protected data
+
+        //- Name of the flux field; default = "phi
+        word phiName_;
+
+        //- Cumulative error
+        scalar cumulative_;
+
+
+    // Protected Member Functions
+
+        //- Output file header information
+        virtual void writeFileHeader(Ostream& os);
+
+
+public:
+
+    //- Runtime type information
+    TypeName("continuityError");
+
+
+    // Constructors
+
+        //- Construct from Time and dictionary
+        continuityError
+        (
+            const word& name,
+            const Time& runTime,
+            const dictionary& dict
+        );
+
+
+    //- Destructor
+    virtual ~continuityError() = default;
+
+
+    // Member Functions
+
+        //- Read the field min/max data
+        virtual bool read(const dictionary&);
+
+        //- Execute, currently does nothing
+        virtual bool execute();
+
+        //- Write the continuityError
+        virtual bool write();
+};
+
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+} // End namespace functionObjects
+} // End namespace Foam
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+#endif
+
+// ************************************************************************* //