ENH: added interpolateSplineXY templated function, and updated tabulated6DoFMotion

src/OpenFOAM/interpolations/interpolateSplineXY/interpolateSplineXY.C

+/*---------------------------------------------------------------------------*\
+  =========                 |
+  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
+   \\    /   O peration     |
+    \\  /    A nd           | Copyright (C) 2010-2010 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 2 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, write to the Free Software Foundation,
+    Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+
+\*---------------------------------------------------------------------------*/
+
+#include "interpolateSplineXY.H"
+#include "primitiveFields.H"
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+template<class Type>
+Foam::Field<Type> Foam::interpolateSplineXY
+(
+    const scalarField& xNew,
+    const scalarField& xOld,
+    const Field<Type>& yOld
+)
+{
+    Field<Type> yNew(xNew.size());
+
+    forAll(xNew, i)
+    {
+        yNew[i] = interpolateSmoothXY(xNew[i], xOld, yOld);
+    }
+
+    return yNew;
+}
+
+
+template<class Type>
+Type Foam::interpolateSplineXY
+(
+    const scalar x,
+    const scalarField& xOld,
+    const Field<Type>& yOld
+)
+{
+    label n = xOld.size();
+
+    // early exit if out of bounds or only one value
+    if (n == 1 || x < xOld[0])
+    {
+        return yOld[0];
+    }
+    if (x > xOld[n - 1])
+    {
+        return yOld[n - 1];
+    }
+
+    // linear interpolation if only two values
+    if (n == 2)
+    {
+        return (x - xOld[0])/(xOld[1] - xOld[0])*(yOld[1] - yOld[0]) + yOld[0];
+    }
+
+    // find bounding knots
+    label hi = 0;
+    while (hi < n && xOld[hi] < x)
+    {
+        hi++;
+    }
+
+    label lo = hi - 1;
+
+    const Type& y1 = yOld[lo];
+    const Type& y2 = yOld[hi];
+
+    Type y0;
+    if (lo == 0)
+    {
+        y0 = 2*y1 - y2;
+    }
+    else
+    {
+        y0 = yOld[lo - 1];
+    }
+
+    Type y3;
+    if (hi + 1 == n)
+    {
+        y3 = 2*y2 - y1;
+    }
+    else
+    {
+        y3 = yOld[hi + 1];
+    }
+
+    // weighting
+    scalar mu = (x - xOld[lo])/(xOld[hi] - xOld[lo]);
+
+    // interpolate
+    return
+        0.5
+       *(
+            2*y1
+          + mu
+           *(
+               -y0 + y2
+              + mu*((2*y0 - 5*y1 + 4*y2 - y3) + mu*(-y0 + 3*y1 - 3*y2 + y3))
+            )
+        );
+}
+
+
+// ************************************************************************* //

src/OpenFOAM/interpolations/interpolateSplineXY/interpolateSplineXY.H

+/*---------------------------------------------------------------------------*\
+  =========                 |
+  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
+   \\    /   O peration     |
+    \\  /    A nd           | Copyright (C) 2010-2010 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 2 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, write to the Free Software Foundation,
+    Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+
+InNamespace
+    Foam
+
+Description
+    Interpolates y values from one curve to another with a different x
+    distribution.
+
+    Uses Catmull-Rom spline interpolation between points.
+
+SourceFiles
+    interpolateSplineXY.C
+
+\*---------------------------------------------------------------------------*/
+
+#ifndef interpolateSplineXY_H
+#define interpolateSplineXY_H
+
+#include "scalar.H"
+#include "primitiveFieldsFwd.H"
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+namespace Foam
+{
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+template<class Type>
+Field<Type> interpolateSplineXY
+(
+    const scalarField& xNew,
+    const scalarField& xOld,
+    const Field<Type>& yOld
+);
+
+
+template<class Type>
+Type interpolateSplineXY
+(
+    const scalar x,
+    const scalarField& xOld,
+    const Field<Type>& yOld
+);
+
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+} // End namespace Foam
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+#ifdef NoRepository
+#   include "interpolateSplineXY.C"
+#endif
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+#endif
+
+// ************************************************************************* //

src/dynamicFvMesh/solidBodyMotionFvMesh/solidBodyMotionFunctions/tabulated6DoFMotion/tabulated6DoFMotion.C

@@ -27,7 +27,7 @@ License
 #include "addToRunTimeSelectionTable.H"
 #include "Tuple2.H"
 #include "IFstream.H"
-#include "interpolateXY.H"
+#include "interpolateSplineXY.H"
 #include "mathematicalConstants.H"
 
 using namespace Foam::constant::mathematical;
@@ -98,7 +98,7 @@ Foam::solidBodyMotionFunctions::tabulated6DoFMotion::transformation() const
             << exit(FatalError);
     }
 
-    translationRotationVectors TRV = interpolateXY
+    translationRotationVectors TRV = interpolateSplineXY
     (
         t,
         times_,