exponential.C

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    Copyright (C) 2011-2016 OpenFOAM Foundation
-------------------------------------------------------------------------------
License
    This file is part of OpenFOAM.
 
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    FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
    for more details.
 
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#include "exponential.H"
#include "addToRunTimeSelectionTable.H"
 
// * * * * * * * * * * * * * * Static Data Members * * * * * * * * * * * * * //
 
namespace Foam
{
namespace distributionModels
{
    defineTypeNameAndDebug(exponential, 0);
    addToRunTimeSelectionTable(distributionModel, exponential, dictionary);
}
}
 
// * * * * * * * * * * * * * * * * Constructors  * * * * * * * * * * * * * * //
 
Foam::distributionModels::exponential::exponential
(
    const dictionary& dict,
    Random& rndGen
)
:
    distributionModel(typeName, dict, rndGen),
    minValue_(distributionModelDict_.get<scalar>("minValue")),
    maxValue_(distributionModelDict_.get<scalar>("maxValue")),
    lambda_(distributionModelDict_.get<scalar>("lambda"))
{
    check();
}
 
 
Foam::distributionModels::exponential::exponential(const exponential& p)
:
    distributionModel(p),
    minValue_(p.minValue_),
    maxValue_(p.maxValue_),
    lambda_(p.lambda_)
{}
 
 
// * * * * * * * * * * * * * * * * Destructor  * * * * * * * * * * * * * * * //
 
Foam::distributionModels::exponential::~exponential()
{}
 
 
// * * * * * * * * * * * * * * * Member Functions  * * * * * * * * * * * * * //
 
Foam::scalar Foam::distributionModels::exponential::sample() const
{
    scalar y = rndGen_.sample01<scalar>();
    scalar K = exp(-lambda_*maxValue_) - exp(-lambda_*minValue_);
    return -(1.0/lambda_)*log(exp(-lambda_*minValue_) + y*K);
}
 
 
Foam::scalar Foam::distributionModels::exponential::minValue() const
{
    return minValue_;
}
 
 
Foam::scalar Foam::distributionModels::exponential::maxValue() const
{
    return maxValue_;
}
 
 
Foam::scalar Foam::distributionModels::exponential::meanValue() const
{
    return 1.0/lambda_;
}
 
 
// ************************************************************************* //