102 lines
2.6 KiB
C++
102 lines
2.6 KiB
C++
//===========================================================================
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//
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// File: Average.hpp<2>
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//
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// Created: Wed Jul 1 12:25:57 2009
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//
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// Author(s): Atgeirr F Rasmussen <atgeirr@sintef.no>
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// Bård Skaflestad <bard.skaflestad@sintef.no>
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//
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// $Date$
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//
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// $Revision$
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//
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//===========================================================================
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/*
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Copyright 2009, 2010 SINTEF ICT, Applied Mathematics.
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Copyright 2009, 2010 Statoil ASA.
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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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#ifndef OPM_AVERAGE_HEADER
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#define OPM_AVERAGE_HEADER
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#include <type_traits>
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#include <cmath>
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namespace Opm {
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namespace utils {
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/// Computes the arithmetic average:
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/// a_A(t_1, t_2) = (t_1 + t_2)/2.
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template <typename T, typename Tresult>
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Tresult arithmeticAverage(const T& t1, const T& t2)
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{
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// To avoid some user errors, we disallow taking averages of
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// integral values.
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static_assert(std::is_integral<T>::value == false, "");
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Tresult retval(t1);
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retval += t2;
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retval *= 0.5;
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return retval;
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}
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/// Computes the geometric average:
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/// a_G(t_1, t_2) = \sqrt{t_1 t_2}.
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/// Since we use std::sqrt(), this function will only
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/// compile when T is convertible to and from double.
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template <typename T>
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T geometricAverage(const T& t1, const T& t2)
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{
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// To avoid some user errors, we disallow taking averages of
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// integral values.
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static_assert(std::is_integral<T>::value == false, "");
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if (t1*t2 <= 0)
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return 0;
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return std::sqrt(t1*t2);
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}
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/// Computes the harmonic average:
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/// a_H(t_1, t_2) = \frac{2}{1/t_1 + 1/t_2} = \frac{2 t_1 t_2}{t_1 + t_2}.
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template <typename T>
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T harmonicAverage(const T& t1, const T& t2)
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{
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// To avoid some user errors, we disallow taking averages of
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// integral values.
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static_assert(std::is_integral<T>::value == false, "");
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if (t1*t2 <= 0)
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return 0;
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return (2*t1*t2)/(t1 + t2);
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}
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} // namespace utils
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} // namespace Opm
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#endif // OPM_AVERAGE_HEADER
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