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foam-extend4.1-coherent-io/applications/utilities/miscellaneous/findRoot/findRoot.C
2016-06-21 15:04:12 +02:00

93 lines
2.4 KiB
C++

/*---------------------------------------------------------------------------*\
========= |
\\ / F ield | foam-extend: Open Source CFD
\\ / O peration | Version: 4.0
\\ / A nd | Web: http://www.foam-extend.org
\\/ M anipulation | For copyright notice see file Copyright
-------------------------------------------------------------------------------
License
This file is part of foam-extend.
foam-extend 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.
foam-extend 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 foam-extend. If not, see <http://www.gnu.org/licenses/>.
Application
findRoot
Description
Test root-finding functions
\*---------------------------------------------------------------------------*/
#include "fvCFD.H"
#include "IOmanip.H"
#include "BisectionRoot.H"
#include "RiddersRoot.H"
#include "NewtonSecantRoot.H"
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
class testFunction
{
public:
testFunction()
{}
scalar operator()(const scalar& x) const
{
return sqr(x) - 1 - Foam::sin(x);
}
};
class testFunctionDerivative
{
public:
testFunctionDerivative()
{}
scalar operator()(const scalar& x) const
{
return 0.5*Foam::pow(x, -1.5) - Foam::cos(x);
}
};
int main(int argc, char *argv[])
{
testFunction tf;
testFunctionDerivative df;
Info<< setprecision(10)
<< "Bisection root "
<< BisectionRoot<testFunction>(tf, 1e-5).root(0, 10) << nl
<< "Ridders root "
<< RiddersRoot<testFunction>(tf, 1e-5).root(0, 10) << nl
<< "NewtonSecant root "
<< NewtonSecantRoot<testFunction, testFunctionDerivative>
(
tf,
df,
1e-5
).root(1.5) << endl;
Info<< "End\n" << endl;
return(0);
}
// ************************************************************************* //