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root/OpenMD/branches/development/src/parallel/Communicator.hpp
Revision: 1549
Committed: Wed Apr 27 18:38:15 2011 UTC (14 years ago) by gezelter
File size: 5346 byte(s)
Log Message:
a few more tweaks   We're getting somewhat closer to deleting fortran.

File Contents

# Content
1 /**
2 * @file Communicator.hpp
3 * @author Charles Vardeman <cvardema.at.nd.edu>
4 * @date 08/18/2010
5 * @time 11:56am
6 * @version 1.0
7 *
8 * @section LICENSE
9 * Copyright (c) 2010 The University of Notre Dame. All Rights Reserved.
10 *
11 * The University of Notre Dame grants you ("Licensee") a
12 * non-exclusive, royalty free, license to use, modify and
13 * redistribute this software in source and binary code form, provided
14 * that the following conditions are met:
15 *
16 * 1. Redistributions of source code must retain the above copyright
17 * notice, this list of conditions and the following disclaimer.
18 *
19 * 2. Redistributions in binary form must reproduce the above copyright
20 * notice, this list of conditions and the following disclaimer in the
21 * documentation and/or other materials provided with the
22 * distribution.
23 *
24 * This software is provided "AS IS," without a warranty of any
25 * kind. All express or implied conditions, representations and
26 * warranties, including any implied warranty of merchantability,
27 * fitness for a particular purpose or non-infringement, are hereby
28 * excluded. The University of Notre Dame and its licensors shall not
29 * be liable for any damages suffered by licensee as a result of
30 * using, modifying or distributing the software or its
31 * derivatives. In no event will the University of Notre Dame or its
32 * licensors be liable for any lost revenue, profit or data, or for
33 * direct, indirect, special, consequential, incidental or punitive
34 * damages, however caused and regardless of the theory of liability,
35 * arising out of the use of or inability to use software, even if the
36 * University of Notre Dame has been advised of the possibility of
37 * such damages.
38 *
39 * SUPPORT OPEN SCIENCE! If you use OpenMD or its source code in your
40 * research, please cite the appropriate papers when you publish your
41 * work. Good starting points are:
42 *
43 * [1] Meineke, et al., J. Comp. Chem. 26, 252-271 (2005).
44 * [2] Fennell & Gezelter, J. Chem. Phys. 124, 234104 (2006).
45 * [3] Sun, Lin & Gezelter, J. Chem. Phys. 128, 24107 (2008).
46 * [4] Vardeman & Gezelter, in progress (2009).
47 */
48
49 #ifndef PARALLEL_COMMUNICATOR_HPP
50 #define PARALLEL_COMMUNICATOR_HPP
51
52 #include <config.h>
53 #include <mpi.h>
54 #include "math/SquareMatrix3.hpp"
55
56 namespace OpenMD{
57
58 #ifdef IS_MPI
59
60 enum communicatorType {
61 Global = 0,
62 Row = 1,
63 Column = 2
64 };
65
66 template<typename T>
67 struct MPITraits
68 {
69 static const MPI::Datatype datatype;
70 static const int dim;
71 };
72
73 template<> const MPI::Datatype MPITraits<int>::datatype = MPI_INT;
74 template<> const int MPITraits<int>::dim = 1;
75 template<> const MPI::Datatype MPITraits<RealType>::datatype = MPI_REALTYPE;
76 template<> const int MPITraits<RealType>::dim = 1;
77 template<> const MPI::Datatype MPITraits<Vector3d>::datatype = MPI_REALTYPE;
78 template<> const int MPITraits<Vector3d>::dim = 3;
79 template<> const MPI::Datatype MPITraits<Mat3x3d>::datatype = MPI_REALTYPE;
80 template<> const int MPITraits<Mat3x3d>::dim = 9;
81
82 template<communicatorType D, typename T>
83 class Communicator {
84 public:
85
86 Communicator<D, T>(int nObjects) {
87
88 int nProc = MPI::COMM_WORLD.Get_size();
89 int myRank = MPI::COMM_WORLD.Get_rank();
90
91 int nColumnsMax = (int) sqrt(RealType(nProc));
92
93 int nColumns;
94 for (int i = 1; i < nColumnsMax + 1; i++) {
95 if (nProc % i == 0) nColumns = i;
96 }
97
98 int nRows = nProc / nColumns;
99 rowIndex_ = myRank / nColumns;
100 columnIndex_ = myRank % nColumns;
101
102 switch(D) {
103 case Row :
104 myComm = MPI::COMM_WORLD.Split(rowIndex_, 0);
105 break;
106 case Column:
107 myComm = MPI::COMM_WORLD.Split(columnIndex_, 0);
108 break;
109 case Global:
110 myComm = MPI::COMM_WORLD.Split(myRank, 0);
111 }
112
113 int nCommProcs = myComm.Get_size();
114
115 counts.reserve(nCommProcs);
116 displacements.reserve(nCommProcs);
117
118 planSize_ = MPITraits<T>::dim * nObjects;
119
120 myComm.Allgather(&planSize_, 1, MPI::INT, &counts[0], 1, MPI::INT);
121
122 displacements[0] = 0;
123 for (int i = 1; i < nCommProcs; i++) {
124 displacements[i] = displacements[i-1] + counts[i-1];
125 size_ += counts[i-1];
126 }
127
128 size_ = 0;
129 for (int i = 0; i < nCommProcs; i++) {
130 size_ += counts[i];
131 }
132 }
133
134
135 void gather(std::vector<T>& v1, std::vector<T>& v2) {
136
137 myComm.Allgatherv(&v1[0],
138 planSize_,
139 MPITraits<T>::datatype,
140 &v2[0],
141 &counts[0],
142 &displacements[0],
143 MPITraits<T>::datatype);
144 }
145
146
147
148 void scatter(std::vector<T>& v1, std::vector<T>& v2) {
149
150 myComm.Reduce_scatter(&v1[0], &v2[0], &counts[0],
151 MPITraits<T>::datatype, MPI::SUM);
152 }
153
154 int getSize() {
155 return size_;
156 }
157
158 private:
159 int planSize_; ///< how many are on local proc
160 int rowIndex_;
161 int columnIndex_;
162 int size_;
163 std::vector<int> counts;
164 std::vector<int> displacements;
165 MPI::Intracomm myComm;
166 };
167
168 #endif
169 }
170 #endif
171
172

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