Zoltan2
Zoltan2_AlgRandom.hpp
Go to the documentation of this file.
1 // @HEADER
2 //
3 // ***********************************************************************
4 //
5 // Zoltan2: A package of combinatorial algorithms for scientific computing
6 // Copyright 2012 Sandia Corporation
7 //
8 // Under the terms of Contract DE-AC04-94AL85000 with Sandia Corporation,
9 // the U.S. Government retains certain rights in this software.
10 //
11 // Redistribution and use in source and binary forms, with or without
12 // modification, are permitted provided that the following conditions are
13 // met:
14 //
15 // 1. Redistributions of source code must retain the above copyright
16 // notice, this list of conditions and the following disclaimer.
17 //
18 // 2. Redistributions in binary form must reproduce the above copyright
19 // notice, this list of conditions and the following disclaimer in the
20 // documentation and/or other materials provided with the distribution.
21 //
22 // 3. Neither the name of the Corporation nor the names of the
23 // contributors may be used to endorse or promote products derived from
24 // this software without specific prior written permission.
25 //
26 // THIS SOFTWARE IS PROVIDED BY SANDIA CORPORATION "AS IS" AND ANY
27 // EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
28 // IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
29 // PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL SANDIA CORPORATION OR THE
30 // CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
31 // EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
32 // PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
33 // PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
34 // LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
35 // NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
36 // SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
37 //
38 // Questions? Contact Karen Devine (kddevin@sandia.gov)
39 // Erik Boman (egboman@sandia.gov)
40 // Siva Rajamanickam (srajama@sandia.gov)
41 //
42 // ***********************************************************************
43 //
44 // @HEADER
45 #ifndef _ZOLTAN2_ALGRANDOM_HPP_
46 #define _ZOLTAN2_ALGRANDOM_HPP_
47 
48 #include <Zoltan2_Algorithm.hpp>
51 
52 
53 namespace Zoltan2{
54 
59 
60 template <typename Adapter>
61 class AlgRandom : public Algorithm<Adapter>
62 {
63  private:
64 
65  const RCP<IdentifierModel<Adapter> > model;
66  const RCP<Teuchos::ParameterList> pl;
67  const RCP<Teuchos::Comm<int> > comm;
68 
69  public:
70 
71  typedef typename Adapter::lno_t lno_t;
72  typedef typename Adapter::gno_t gno_t;
73 
75  const RCP<IdentifierModel<Adapter> > &model__,
76  const RCP<Teuchos::ParameterList> &pl__,
77  const RCP<Teuchos::Comm<int> > &comm__
78  ) : model(model__), pl(pl__), comm(comm__)
79  {
80  }
81 
82  int order(const RCP<OrderingSolution<lno_t, gno_t> > &solution)
83  {
84 
85  int ierr= 0;
86 
87  HELLO;
88 
89  // This is the Fisher-Yates shuffle (aka Knuth shuffle).
90  // References:
91  // R.A. Fisher, F. Yates, (1948) [1938], Statistical tables for biological, agricultural and medical research (3rd ed.).
92  // R. Durstenfeld, "Algorithm 235: Random permutation", CACM, vol. 7, 1964.
93  // D.E. Knuth, "The Art of Computer Programming", volume 2, 1969.
94 
95  // Start with the identity permutation.
96  const size_t n = model->getLocalNumIdentifiers();
97  lno_t *perm;
98  perm = (lno_t *) (solution->getPermutationRCP().getRawPtr());
99  if (perm){
100  for (size_t i=0; i<n; i++){
101  perm[i] = i;
102  }
103  }
104  else
105  // throw exception?
106  ierr = -1;
107 
108  // Swap random pairs of indices in perm.
109  lno_t j, temp;
110  for (lno_t i=n-1; i>0; i--){
111  // Choose j randomly in [0,i]
112  j = rand() % (i+1);
113  // Swap (perm[i], perm[j])
114  temp = perm[i];
115  perm[i] = perm[j];
116  perm[j] = temp;
117  }
118 
119  solution->setHavePerm(true);
120  return ierr;
121 
122  }
123 
124 };
125 }
126 #endif
#define HELLO
Defines the OrderingSolution class.
AlgRandom(const RCP< IdentifierModel< Adapter > > &model__, const RCP< Teuchos::ParameterList > &pl__, const RCP< Teuchos::Comm< int > > &comm__)
Defines the IdentifierModel interface.
Algorithm defines the base class for all algorithms.
IdentifierModel defines the interface for all identifier models.
The class containing ordering solutions.
int order(const RCP< OrderingSolution< lno_t, gno_t > > &solution)
Ordering method.