db7fac3f24
git-svn-id: https://openfoam-extend.svn.sourceforge.net/svnroot/openfoam-extend/trunk/Core/OpenFOAM-1.5-dev@1731 e4e07f05-0c2f-0410-a05a-b8ba57e0c909
158 lines
4.1 KiB
C
158 lines
4.1 KiB
C
/*---------------------------------------------------------------------------*\
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========= |
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\\ / F ield | OpenFOAM: The Open Source CFD Toolbox
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\\ / O peration |
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\\ / A nd | Copyright held by original author
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\\/ M anipulation |
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-------------------------------------------------------------------------------
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License
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This file is part of OpenFOAM.
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OpenFOAM is free software; you can redistribute it and/or modify it
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under the terms of the GNU General Public License as published by the
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Free Software Foundation; either version 2 of the License, or (at your
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option) any later version.
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OpenFOAM is distributed in the hope that it will be useful, but WITHOUT
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ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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for more details.
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You should have received a copy of the GNU General Public License
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along with OpenFOAM; if not, write to the Free Software Foundation,
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Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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Description
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BSpline : cubic spline going through all the knots
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\*---------------------------------------------------------------------------*/
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#include "error.H"
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#include "BSpline.H"
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#include "simpleMatrix.H"
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// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
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namespace Foam
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{
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pointField BSpline::findKnots
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(
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const pointField& allknots,
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const vector& fstend,
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const vector& sndend
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)
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{
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label newnKnots(allknots.size() + 2);
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label NKnots(allknots.size());
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pointField newknots(newnKnots);
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// set up 1/6 and 2/3 which are the matrix elements throughout most
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// of the matrix
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register scalar oneSixth = 1.0/6.0;
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register scalar twoThird = 2.0/3.0;
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simpleMatrix<vector> M(newnKnots);
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// set up the matrix
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M[0][0] = -0.5*scalar(NKnots - 1);
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M[0][2] = 0.5*scalar(NKnots - 1);
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for (register label i=1; i<newnKnots-1; i++)
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{
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M[i][i-1] = oneSixth;
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M[i][i] = twoThird;
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M[i][i+1] = oneSixth;
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}
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M[newnKnots - 1][newnKnots - 3] = -0.5*scalar(NKnots - 1);
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M[newnKnots - 1][newnKnots - 1] = 0.5*scalar(NKnots - 1);
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// set up the vector
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for (label i=1; i<=NKnots; i++)
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{
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M.source()[i] = allknots[i-1];
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}
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// set the gradients at the two ends
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if (mag(fstend)<1e-8)
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{
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// set to the default : forward differences on the end knots
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M.source()[0] = allknots[1] - allknots[0];
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M.source()[0] /= mag(M.source()[0]);
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M.source()[NKnots+1] = M.source()[NKnots-1] - M.source()[NKnots];
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M.source()[NKnots+1] /= mag(M.source()[NKnots+1]);
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}
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else
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{
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// set to the gradient vectors provided
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M.source()[0] = fstend/mag(fstend);
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M.source()[NKnots+1] = sndend/mag(sndend);
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}
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// invert the equation to find the control knots
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newknots = M.solve();
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return newknots;
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}
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// * * * * * * * * * * * * * * * * Constructors * * * * * * * * * * * * * * //
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// Construct from components
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BSpline::BSpline(const pointField& Knots)
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:
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spline(findKnots(Knots))
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{}
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// Construct from components
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BSpline::BSpline
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(
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const pointField& Knots,
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const vector& fstend,
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const vector& sndend
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)
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:
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spline(findKnots(Knots, fstend, sndend))
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{}
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// * * * * * * * * * * * * * * * Member Functions * * * * * * * * * * * * * //
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//- Return the real position of a point on the curve given by
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// the parameter 0 <= lambda <= 1
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vector BSpline::realPosition(scalar mu)
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{
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return spline::position(mu);
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}
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//- Return the position of a point on the curve given by
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// the parameter 0 <= lambda <= 1
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vector BSpline::position(const scalar mu) const
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{
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return spline::position((1.0/(nKnots() - 1))*(1.0 + mu*(nKnots() - 3)));
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}
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//- Return the length of the curve
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scalar BSpline::length() const
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{
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notImplemented("BSpline::length() const");
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return 1.0;
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}
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// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
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} // End namespace Foam
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// ************************************************************************* //
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