VDmath.hpp

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///////////////////////////////////////////////////////////////////////////////
//
// File: VDmath.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).
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the "Software"),
// to deal in the Software without restriction, including without limitation
// the rights to use, copy, modify, merge, publish, distribute, sublicense,
// and/or sell copies of the Software, and to permit persons to whom the
// Software is furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included
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// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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//
// Description: Collection of templated functions for distributed vector
//              mathematics
//
///////////////////////////////////////////////////////////////////////////////
 
#ifndef NEKTAR_LIB_LIBUTILITIES_BASSICUTILS_VECTORDISTMATH_HPP
#define NEKTAR_LIB_LIBUTILITIES_BASSICUTILS_VECTORDISTMATH_HPP
 
#include <LibUtilities/Communication/Comm.h>
 
namespace VDmath
{
/// \brief  dot2 (vector times vector times vector): z = w*x*y
template <class T>
T Ddot2(Nektar::LibUtilities::CommSharedPtr &pComm, int n, const T *w,
        const T *x, const int *y)
{
    T sum = 0;
 
    while (n--)
    {
        sum += (*y == 1 ? (*w) * (*x) : 0);
        ++w;
        ++x;
        ++y;
    }
    pComm->AllReduce(sum, Nektar::LibUtilities::ReduceSum);
    return sum;
}
 
/// \brief  dot2 (vector times vector times vector): z = w*x*y
template <class T>
T Ddot2(Nektar::LibUtilities::CommSharedPtr &pComm, int n, const T *w,
        const int incw, const T *x, const int incx, const int *y,
        const int incy)
{
    T sum = 0;
 
    while (n--)
    {
        sum += (*y == 1 ? (*w) * (*x) : 0.0);
        w += incw;
        x += incx;
        y += incy;
    }
    pComm->AllReduce(sum, Nektar::LibUtilities::ReduceSum);
    return sum;
}
} // namespace VDmath
#endif /* DVMATH_HPP_ */