ENH: add 'cellCentre' sampledSet (issue #869)

- samples on cell centres, can optionally limit based on a bounding box.
  Can be used, for example, to extract volume fields into CSV format.

src/sampling/Make/files

@@ -6,6 +6,7 @@ sampledSet/circle/circleSet.C
 sampledSet/cloud/cloudSet.C
 sampledSet/patchCloud/patchCloudSet.C
 sampledSet/polyLine/polyLineSet.C
+sampledSet/cellCentre/cellCentreSet.C
 sampledSet/face/faceOnlySet.C
 sampledSet/midPoint/midPointSet.C
 sampledSet/midPointAndFace/midPointAndFaceSet.C

src/sampling/sampledSet/cellCentre/cellCentreSet.C

@@ -0,0 +1,132 @@
+/*---------------------------------------------------------------------------*\
+  =========                 |
+  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
+   \\    /   O peration     |
+    \\  /    A nd           | Copyright (C) 2018 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/>.
+
+\*---------------------------------------------------------------------------*/
+
+#include "cellCentreSet.H"
+#include "meshSearch.H"
+#include "polyMesh.H"
+#include "volFields.H"
+#include "addToRunTimeSelectionTable.H"
+
+// * * * * * * * * * * * * * * Static Data Members * * * * * * * * * * * * * //
+
+namespace Foam
+{
+    defineTypeNameAndDebug(cellCentreSet, 0);
+    addToRunTimeSelectionTable(sampledSet, cellCentreSet, word);
+}
+
+
+// * * * * * * * * * * * * * Private Member Functions  * * * * * * * * * * * //
+
+void Foam::cellCentreSet::genSamples()
+{
+    const label len = mesh().nCells();
+
+    const auto& cellCentres =
+        refCast<const fvMesh>(mesh()).C().primitiveField();
+
+    labelList selectedCells = identity(len);
+    List<point> selectedPoints;
+
+    if (bounds_.empty())
+    {
+        selectedPoints = cellCentres;
+    }
+    else
+    {
+        label count = 0;
+        for (label celli=0; celli < len; ++celli)
+        {
+            if (bounds_.contains(cellCentres[celli]))
+            {
+                selectedCells[count++] = celli;
+            }
+        }
+
+        selectedCells.resize(count);
+        selectedPoints = UIndirectList<point>(cellCentres, selectedCells);
+    }
+
+    labelList samplingFaces(selectedCells.size(), -1);
+    labelList samplingSegments(selectedCells.size(), -1);
+    scalarList samplingCurveDist(selectedCells.size(), 0.0);
+
+    // Move into *this
+    setSamples
+    (
+        std::move(selectedPoints),
+        std::move(selectedCells),
+        std::move(samplingFaces),
+        std::move(samplingSegments),
+        std::move(samplingCurveDist)
+    );
+
+    if (debug)
+    {
+        write(Info);
+    }
+}
+
+
+// * * * * * * * * * * * * * * * * Constructors  * * * * * * * * * * * * * * //
+
+Foam::cellCentreSet::cellCentreSet
+(
+    const word& name,
+    const polyMesh& mesh,
+    const meshSearch& searchEngine,
+    const word& axis,
+    const boundBox& bbox
+)
+:
+    sampledSet(name, mesh, searchEngine, axis),
+    bounds_(bbox)
+{
+    genSamples();
+}
+
+
+Foam::cellCentreSet::cellCentreSet
+(
+    const word& name,
+    const polyMesh& mesh,
+    const meshSearch& searchEngine,
+    const dictionary& dict
+)
+:
+    sampledSet
+    (
+        name,
+        mesh,
+        searchEngine,
+        dict.lookupOrDefault<word>("axis", "xyz")
+    ),
+    bounds_(dict.lookupOrDefault("bounds", boundBox::invertedBox))
+{
+    genSamples();
+}
+
+
+// ************************************************************************* //

src/sampling/sampledSet/cellCentre/cellCentreSet.H

@@ -0,0 +1,115 @@
+/*---------------------------------------------------------------------------*\
+  =========                 |
+  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
+   \\    /   O peration     |
+    \\  /    A nd           | Copyright (C) 2018 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::cellCentreSet
+
+Description
+    A sampleSet based on cell centres
+
+    For a dictionary specification:
+    \table
+        Property | Description                             | Required | Default
+        type     | cellCentre                              | yes      |
+        axis     | x, y, z, xyz, distance                  | no       | xyz
+        bounds   | limit with bounding box                 | no       |
+    \endtable
+
+SourceFiles
+    cellCentreSet.C
+
+\*---------------------------------------------------------------------------*/
+
+#ifndef cellCentreSet_H
+#define cellCentreSet_H
+
+#include "sampledSet.H"
+#include "boundBox.H"
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+namespace Foam
+{
+
+/*---------------------------------------------------------------------------*\
+                        Class cellCentreSet Declaration
+\*---------------------------------------------------------------------------*/
+
+class cellCentreSet
+:
+    public sampledSet
+{
+    // Private data
+
+        //- Optional bounding box to restrict the geometry
+        const boundBox bounds_;
+
+
+    // Private Member Functions
+
+        //- Generate samples
+        void genSamples();
+
+
+public:
+
+    //- Runtime type information
+    TypeName("cellCentre");
+
+
+    // Constructors
+
+        //- Construct from components
+        cellCentreSet
+        (
+            const word& name,
+            const polyMesh& mesh,
+            const meshSearch& searchEngine,
+            const word& axis,
+            const boundBox& bbox = boundBox::invertedBox
+        );
+
+        //- Construct from dictionary
+        cellCentreSet
+        (
+            const word& name,
+            const polyMesh& mesh,
+            const meshSearch& searchEngine,
+            const dictionary& dict
+        );
+
+
+    //- Destructor
+    virtual ~cellCentreSet() = default;
+};
+
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+} // End namespace Foam
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+#endif
+
+// ************************************************************************* //

tutorials/compressible/rhoSimpleFoam/squareBend/system/controlDict

@@ -53,6 +53,7 @@ functions
 {
     #include "sampling"
     // #include "samplingDebug"
+    // #include "sampleCellCentres"
 }
 
 

tutorials/compressible/rhoSimpleFoam/squareBend/system/sampleCellCentres

@@ -0,0 +1,34 @@
+// -*- C++ -*-
+
+sampleSets
+{
+    type    sets;
+    libs    ("libsampling.so");
+    log     on;
+    enabled true;
+
+    writeControl    timeStep;
+    writeInterval   10;
+
+    setFormat       vtk;
+    setFormat       csv;
+    interpolationScheme cell;
+
+    // fields ( U p );
+
+    fields ( U );
+
+    sets
+    (
+        centres
+        {
+            type    cellCentre;
+            // axis    xyz;  // default: xyz
+
+            // bounds  (-0.2 -1 -1) (-0.195 0 1);
+            bounds  (-0.025 -1 -1) (-0.0225 0 1);  // single cell layer
+        }
+    );
+}
+
+// ************************************************************************* //