99a61df00a
conceptually, this may not be the purest conceivable solution, but it is the most practical one.
83 lines
1.9 KiB
C++
83 lines
1.9 KiB
C++
// -*- mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
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// vi: set et ts=4 sw=4 sts=4:
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/*
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Copyright 2015 Andreas Lauser
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This file is part of the Open Porous Media project (OPM).
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OPM is free software: you can redistribute it and/or modify
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it 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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OPM is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License 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 OPM. If not, see <http://www.gnu.org/licenses/>.
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*/
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/*!
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* \file
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*
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* \brief Implements some common averages.
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*
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* i.e., arithmetic, geometric and harmonic averages.
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*/
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#ifndef OPM_MEANS_HH
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#define OPM_MEANS_HH
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#include <cmath>
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namespace Opm {
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/*!
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* \brief Computes the arithmetic average of two values.
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*
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* This uses the usual definition of the arithmethic mean:
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* \f[
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<a(x,y)> = (x+y)/2
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\f]
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*/
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template <class Scalar>
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inline Scalar arithmeticMean(Scalar x, Scalar y)
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{ return (x+y)/2; }
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/*!
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* \brief Computes the geometric average of two values.
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*
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* This uses the usual definition of the geometric mean:
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* \f[
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<a(x,y)> = \sqrt{x^2 + y^2}
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\f]
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*/
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template <class Scalar>
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inline Scalar geometricMean(Scalar x, Scalar y)
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{
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if (x*y <= 0.0)
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return 0.0;
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return std::sqrt(x*x + y*y);
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}
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/*!
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* \brief Computes the harmonic average of two values.
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*
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* This uses the usual definition of the harmonic mean:
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* \f[
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<a(x,y)> = \frac{2}{1/x + 1/y}
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\f]
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*/
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template <class Scalar>
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inline Scalar harmonicMean(Scalar x, Scalar y)
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{
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if (x*y <= 0)
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return 0.0;
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return (2*x*y)/(y + x);
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}
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} // namespace Ewoms
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#endif // EWOMS_AVERAGE_HH
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