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VDmath.hpp
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1 ///////////////////////////////////////////////////////////////////////////////
2 //
3 // File DVmath.hpp
4 //
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7 // The MIT License
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9 // Copyright (c) 2006 Division of Applied Mathematics, Brown University (USA),
10 // Department of Aeronautics, Imperial College London (UK), and Scientific
11 // Computing and Imaging Institute, University of Utah (USA).
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31 //
32 // Description: Collection of templated functions for distributed vector
33 // mathematics
34 //
35 ///////////////////////////////////////////////////////////////////////////////
36 
37 #ifndef NEKTAR_LIB_LIBUTILITIES_BASSICUTILS_VECTORDISTMATH_HPP
38 #define NEKTAR_LIB_LIBUTILITIES_BASSICUTILS_VECTORDISTMATH_HPP
39 
41 
42 namespace VDmath
43 {
44  /// \brief vvtvp (vector times vector times vector): z = w*x*y
45  template<class T> T Ddot2( Nektar::LibUtilities::CommSharedPtr& pComm,
46  int n,
47  const T *w,
48  const T *x,
49  const int *y)
50  {
51  T sum = 0;
52 
53  while( n-- )
54  {
55  sum += (*y == 1 ? (*w) * (*x) : 0 );
56  ++w;
57  ++x;
58  ++y;
59  }
60  pComm->AllReduce(sum, Nektar::LibUtilities::ReduceSum);
61  return sum;
62  }
63 
64  /// \brief vvtvp (vector times vector times vector): z = w*x*y
65  template<class T> T Ddot2( Nektar::LibUtilities::CommSharedPtr& pComm,
66  int n,
67  const T *w, const int incw,
68  const T *x, const int incx,
69  const int *y, const int incy)
70  {
71  T sum = 0;
72 
73  while( n-- )
74  {
75  sum += (*y == 1 ? (*w) * (*x) : 0.0 );
76  w += incw;
77  x += incx;
78  y += incy;
79  }
80  pComm->AllReduce(sum, Nektar::LibUtilities::ReduceSum);
81  return sum;
82  }
83 }
84 #endif /* DVMATH_HPP_ */