Files
opm-common/opm/material/common/Means.hpp
Andreas Lauser da401551be clean up the licensing preable of source files
this patch removes the in-file lists in favor of a global list of in
the COPYING file. this is done because (a) maintaining a list of
authors at the beginning of each source file is a major pain in the
a**, (b) for this reason, the list of authors was not accurate in
about 85% of all cases where more than one person was involved and (c)
this list is not legally binding in any way (the copyright is at the
person who authored a given change; if these lists had any legal
relevance, one could "aquire" the copyright of the module by forking
it and replacing the lists...)
2016-03-15 00:58:09 +01:00

85 lines
2.0 KiB
C++

// -*- mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
// vi: set et ts=4 sw=4 sts=4:
/*
This file is part of the Open Porous Media project (OPM).
OPM 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 2 of the License, or
(at your option) any later version.
OPM 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 OPM. If not, see <http://www.gnu.org/licenses/>.
Consult the COPYING file in the top-level source directory of this
module for the precise wording of the license and the list of
copyright holders.
*/
/*!
* \file
*
* \brief Implements some common averages.
*
* i.e., arithmetic, geometric and harmonic averages.
*/
#ifndef OPM_MEANS_HH
#define OPM_MEANS_HH
#include <cmath>
namespace Opm {
/*!
* \brief Computes the arithmetic average of two values.
*
* This uses the usual definition of the arithmethic mean:
* \f[
<a(x,y)> = (x+y)/2
\f]
*/
template <class Scalar>
inline Scalar arithmeticMean(Scalar x, Scalar y)
{ return (x+y)/2; }
/*!
* \brief Computes the geometric average of two values.
*
* This uses the usual definition of the geometric mean:
* \f[
<a(x,y)> = \sqrt{x^2 + y^2}
\f]
*/
template <class Scalar>
inline Scalar geometricMean(Scalar x, Scalar y)
{
if (x*y <= 0.0)
return 0.0;
return std::sqrt(x*y);
}
/*!
* \brief Computes the harmonic average of two values.
*
* This uses the usual definition of the harmonic mean:
* \f[
<a(x,y)> = \frac{2}{1/x + 1/y}
\f]
*/
template <class Scalar>
inline Scalar harmonicMean(Scalar x, Scalar y)
{
if (x*y <= 0)
return 0.0;
return (2*x*y)/(y + x);
}
} // namespace Ewoms
#endif // EWOMS_AVERAGE_HH