Smath.hpp

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///////////////////////////////////////////////////////////////////////////////
//
// File: Smath.hpp
//
// For more information, please see: http://www.nektar.info
//
// The MIT License
//
// Copyright (c) 2006 Division of Applied Mathematics, Brown University (USA),
// Department of Aeronautics, Imperial College London (UK), and Scientific
// Computing and Imaging Institute, University of Utah (USA).
//
// License for the specific language governing rights and limitations under
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// Description: Collection of templated functions for scalar mathematics
//
///////////////////////////////////////////////////////////////////////////////
 
#ifndef NEKTAR_LIB_LIBUTILITIES_BASSICUTILS_SCALARMATH_H
#define NEKTAR_LIB_LIBUTILITIES_BASSICUTILS_SCALARMATH_H
 
#include <LibUtilities/BasicConst/NektarUnivTypeDefs.hpp>
#include <LibUtilities/LibUtilitiesDeclspec.h>
#include <algorithm>
#include <cstdlib>
#include <math.h>
 
using namespace Nektar;
 
namespace Smath
{
 
/***************** Math routines  ***************/
 
/// \brief Return the soft max of between two scalars
template <class T> T Smax(const T a, const T b, const T k)
{
    T maxi = std::max(a, b) * k;
    T mini = std::min(a, b) * k;
    T xmax = (maxi + log(1.0 + exp(mini - maxi))) / k;
    return xmax;
}
 
template NekDouble Smax(const NekDouble a, const NekDouble b,
                        const NekDouble k);
 
template int Smax(const int a, const int b, const int k);
} // namespace Smath
#endif // NEKTAR_LIB_LIBUTILITIES_BASSICUTILS_SCALARMATH_H