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112 lines
2.9 KiB
C
112 lines
2.9 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 (C) 1991-2010 OpenCFD Ltd.
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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
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the Free Software Foundation, either version 3 of the License, or
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(at your 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, see <http://www.gnu.org/licenses/>.
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\*---------------------------------------------------------------------------*/
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#include "ODESolver.H"
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// * * * * * * * * * * * * * * Static Data Members * * * * * * * * * * * * * //
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defineTypeNameAndDebug(Foam::ODESolver, 0);
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namespace Foam
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{
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defineRunTimeSelectionTable(ODESolver, ODE);
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};
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// * * * * * * * * * * * * * * * * Constructors * * * * * * * * * * * * * * //
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Foam::ODESolver::ODESolver(const ODE& ode)
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:
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n_(ode.nEqns()),
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yScale_(n_),
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dydx_(n_)
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{}
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// * * * * * * * * * * * * * * * Member Functions * * * * * * * * * * * * * //
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void Foam::ODESolver::solve
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(
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const ODE& ode,
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const scalar xStart,
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const scalar xEnd,
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scalarField& y,
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const scalar eps,
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scalar& hEst
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) const
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{
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const label MAXSTP = 10000;
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scalar x = xStart;
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scalar h = hEst;
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scalar hNext = 0;
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scalar hPrev = 0;
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for (label nStep=0; nStep<MAXSTP; nStep++)
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{
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ode.derivatives(x, y, dydx_);
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for (label i=0; i<n_; i++)
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{
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yScale_[i] = mag(y[i]) + mag(dydx_[i]*h) + SMALL;
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}
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if ((x + h - xEnd)*(x + h - xStart) > 0.0)
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{
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h = xEnd - x;
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hPrev = hNext;
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}
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hNext = 0;
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scalar hDid;
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solve(ode, x, y, dydx_, eps, yScale_, h, hDid, hNext);
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if ((x - xEnd)*(xEnd - xStart) >= 0.0)
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{
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if (hPrev != 0)
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{
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hEst = hPrev;
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}
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else
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{
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hEst = hNext;
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}
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return;
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}
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h = hNext;
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}
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FatalErrorIn
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(
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"ODESolver::solve"
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"(const ODE& ode, const scalar xStart, const scalar xEnd,"
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"scalarField& yStart, const scalar eps, scalar& hEst) const"
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) << "Too many integration steps"
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<< exit(FatalError);
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}
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// ************************************************************************* //
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