ENH: additional methods/operators for boundBox (related to #196)

- Constructor for bounding box of a single point.

- add(boundBox), add(point) ...
  -> Extend box to enclose the second box or point(s).

  Eg,
      bb.add(pt);
  vs.
      bb.min() = Foam::min(bb.min(), pt);
      bb.max() = Foam::max(bb.max(), pt);

Also works with other bounding boxes.
  Eg,
      bb.add(bb2);
      // OR
      bb += bb2;
  vs.
      bb.min() = Foam::min(bb.min(), bb2.min());
      bb.max() = Foam::max(bb.max(), bb2.max());

'+=' operator allows the reduction to be used in parallel
gather/scatter operations.

A global '+' operator is not currently needed.

Note: may be useful in the future to have a 'clear()' method
that resets to a zero-sized (inverted) box.

STYLE: make many bounding box constructors explicit

src/sampling/meshToMesh/meshToMeshParallelOps.C

@@ -3,7 +3,7 @@
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     |
     \\  /    A nd           | Copyright (C) 2012-2016 OpenFOAM Foundation
-     \\/     M anipulation  | Copyright (C) 2015 OpenCFD Ltd.
+     \\/     M anipulation  | Copyright (C) 2015-2017 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -177,14 +177,13 @@ Foam::autoPtr<Foam::mapDistribute> Foam::meshToMesh::calcProcMap
             const cell& c = cells[celli];
 
             // determine bounding box of tgt cell
-            boundBox cellBb(point::max, point::min);
+            boundBox cellBb(boundBox::invertedBox);
             forAll(c, facei)
             {
                 const face& f = faces[c[facei]];
                 forAll(f, fp)
                 {
-                    cellBb.min() = min(cellBb.min(), points[f[fp]]);
-                    cellBb.max() = max(cellBb.max(), points[f[fp]]);
+                    cellBb.add(points, f);
                 }
             }
 

src/sampling/probes/patchProbes.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 OpenCFD Ltd.
+     \\/     M anipulation  | Copyright (C) 2016-2017 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -79,12 +79,9 @@ void Foam::patchProbes::findElements(const fvMesh& mesh)
             {
                 bndFaces[nFaces++] = pp.start()+i;
                 const face& f = pp[i];
-                forAll(f, fp)
-                {
-                    const point& pt = pp.points()[f[fp]];
-                    overallBb.min() = min(overallBb.min(), pt);
-                    overallBb.max() = max(overallBb.max(), pt);
-                }
+
+                // Without reduction.
+                overallBb.add(pp.points(), f);
             }
         }
 

src/sampling/sampledSet/patchCloud/patchCloudSet.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  |
+     \\/     M anipulation  | Copyright (C) 2017 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -74,7 +74,7 @@ void Foam::patchCloudSet::calcSamples
 
     labelList patchFaces(sz);
     sz = 0;
-    treeBoundBox bb(point::max, point::min);
+    treeBoundBox bb(treeBoundBox::invertedBox);
     forAllConstIter(labelHashSet, patchSet_, iter)
     {
         const polyPatch& pp = mesh().boundaryMesh()[iter.key()];
@@ -84,11 +84,8 @@ void Foam::patchCloudSet::calcSamples
             patchFaces[sz++] = pp.start()+i;
         }
 
-        // Do not do reduction.
-        const boundBox patchBb(pp.points(), pp.meshPoints(), false);
-
-        bb.min() = min(bb.min(), patchBb.min());
-        bb.max() = max(bb.max(), patchBb.max());
+        // Without reduction.
+        bb.add(pp.points(), pp.meshPoints());
     }
 
     // Not very random
@@ -97,8 +94,8 @@ void Foam::patchCloudSet::calcSamples
     bb = bb.extend(rndGen, 1e-4);
 
     // Make sure bb is 3D.
-    bb.min() -= point(ROOTVSMALL, ROOTVSMALL, ROOTVSMALL);
-    bb.max() += point(ROOTVSMALL, ROOTVSMALL, ROOTVSMALL);
+    bb.min() -= point::uniform(ROOTVSMALL);
+    bb.max() += point::uniform(ROOTVSMALL);
 
 
     indexedOctree<treeDataFace> patchTree

src/sampling/sampledSurface/sampledTriSurfaceMesh/sampledTriSurfaceMesh.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 OpenCFD Ltd.
+     \\/     M anipulation  | Copyright (C) 2016-2017 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -778,8 +778,8 @@ bool Foam::sampledTriSurfaceMesh::update()
         surface_.triSurface::points(),
         surface_.triSurface::meshPoints()
     );
-    bb.min() = max(bb.min(), mesh().bounds().min());
-    bb.max() = min(bb.max(), mesh().bounds().max());
+
+    bb.intersect(mesh().bounds());
 
     // Extend a bit
     const vector span(bb.span());