1 // Copyright Daniel Wallin 2007. Use, modification and distribution is
2 // subject to the Boost Software License, Version 1.0. (See accompanying
3 // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
4 
5 #ifndef BOOST_SHUFFLED_DISTRIBUTION_070923_HPP
6 #define BOOST_SHUFFLED_DISTRIBUTION_070923_HPP
7 
8 #ifndef BOOST_GRAPH_USE_MPI
9 #error "Parallel BGL files should not be included unless <boost/graph/use_mpi.hpp> has been included"
10 #endif
11 
12 # include <boost/assert.hpp>
13 # include <boost/iterator/counting_iterator.hpp>
14 # include <vector>
15 
16 namespace boost { namespace graph { namespace distributed {
17 
18 template <class BaseDistribution>
19 struct shuffled_distribution : BaseDistribution
20 {
21     typedef std::size_t size_type;
22 
23     template <class ProcessGroup>
shuffled_distributionboost::graph::distributed::shuffled_distribution24     shuffled_distribution(ProcessGroup const& pg, BaseDistribution const& base)
25       : BaseDistribution(base)
26       , n(num_processes(pg))
27       , mapping_(make_counting_iterator(size_type(0)), make_counting_iterator(n))
28       , reverse_mapping(mapping_)
29     {}
30 
mappingboost::graph::distributed::shuffled_distribution31     std::vector<size_type> const& mapping() const
32     {
33         return mapping_;
34     }
35 
36     template <class InputIterator>
assign_mappingboost::graph::distributed::shuffled_distribution37     void assign_mapping(InputIterator first, InputIterator last)
38     {
39         mapping_.assign(first, last);
40         BOOST_ASSERT(mapping_.size() == n);
41         reverse_mapping.resize(mapping_.size());
42 
43         for (std::vector<size_t>::iterator i(mapping_.begin());
44             i != mapping_.end(); ++i)
45         {
46             reverse_mapping[*i] = i - mapping_.begin();
47         }
48     }
49 
baseboost::graph::distributed::shuffled_distribution50     BaseDistribution& base()
51     {
52         return *this;
53     }
54 
baseboost::graph::distributed::shuffled_distribution55     BaseDistribution const& base() const
56     {
57         return *this;
58     }
59 
60     template <class ProcessID>
block_sizeboost::graph::distributed::shuffled_distribution61     size_type block_size(ProcessID id, size_type n) const
62     {
63         return base().block_size(reverse_mapping[id], n);
64     }
65 
66     template <class T>
operator ()boost::graph::distributed::shuffled_distribution67     size_type operator()(T const& value) const
68     {
69         return mapping_[base()(value)];
70     }
71 
72     template <class ProcessID>
startboost::graph::distributed::shuffled_distribution73     size_type start(ProcessID id) const
74     {
75         return base().start(reverse_mapping[id]);
76     }
77 
localboost::graph::distributed::shuffled_distribution78     size_type local(size_type i) const
79     {
80         return base().local(i);
81     }
82 
globalboost::graph::distributed::shuffled_distribution83     size_type global(size_type i) const
84     {
85         return base().global(i);
86     }
87 
88     template <class ProcessID>
globalboost::graph::distributed::shuffled_distribution89     size_type global(ProcessID id, size_type n) const
90     {
91         return base().global(reverse_mapping[id], n);
92     }
93 
94     template <class Archive>
serializeboost::graph::distributed::shuffled_distribution95     void serialize(Archive& ar, unsigned long /*version*/)
96     {
97         ar & serialization::make_nvp("base", base());
98     }
99 
clearboost::graph::distributed::shuffled_distribution100     void clear()
101     {
102         base().clear();
103     }
104 
105 private:
106     size_type n;
107     std::vector<size_type> mapping_;
108     std::vector<size_type> reverse_mapping;
109 };
110 
111 }}} // namespace boost::graph::distributed
112 
113 #endif // BOOST_SHUFFLED_DISTRIBUTION_070923_HPP
114 
115