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Fix silly error pointed out by Gordon Smith

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[SVN r24537]
This commit is contained in:
Douglas Gregor
2004-08-17 20:46:38 +00:00
parent a55c13e6a8
commit 6a485be22b
1 changed files with 48 additions and 98 deletions
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146
include/boost/graph/random.hpp
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@@ -225,112 +225,62 @@ namespace boost {
(g, rg, Property(), typename property_kind<Property>::type());
}
template<typename SizeType, typename Probability,
typename RandomGenerator = minstd_rand>
class erdos_renyi_random_iterator
: public iterator_facade<
erdos_renyi_random_iterator<SizeType,Probability,RandomGenerator>
, std::pair<SizeType, SizeType>
, std::input_iterator_tag
, std::pair<SizeType, SizeType>
>
template<typename MutableGraph, typename Real, typename RandomNumGen>
void
erdos_renyi_random_graph
(MutableGraph& g,
typename graph_traits<MutableGraph>::vertices_size_type n,
Real edge_probability,
bool allow_self_loops,
RandomNumGen& gen)
{
typedef erdos_renyi_random_iterator self_type;
typedef iterator_facade<
erdos_renyi_random_iterator<SizeType,Probability,RandomGenerator>
, std::pair<SizeType, SizeType>
, std::input_iterator_tag
, std::pair<SizeType, SizeType>
> inherited;
public:
typedef typename inherited::reference reference;
typedef typename inherited::value_type value_type;
typedef typename graph_traits<MutableGraph>::vertex_iterator
vertex_iterator;
typedef typename graph_traits<MutableGraph>::vertex_descriptor
vertex_descriptor;
typedef typename graph_traits<MutableGraph>::vertices_size_type
vertices_size_type;
typedef typename graph_traits<MutableGraph>::edges_size_type
edges_size_type;
// Determine if the graph is undirected
typedef typename graph_traits<MutableGraph>::directed_category
directed_category;
const bool is_undirected =
is_convertible<directed_category*, undirected_tag*>::value;
// Starting iterator for n vertices with probability p using gen
// as the random number generator.
erdos_renyi_random_iterator(SizeType n, Probability p,
RandomGenerator& gen, bool directed,
bool self_edges = false)
: n(n), p(p),
random_(new uniform_01<RandomGenerator, Probability>(gen)),
directed(directed), self_edges(self_edges),
current_edge(static_cast<SizeType>(0), static_cast<SizeType>(0))
{
for (/* no init */; current_edge.first < n; ++current_edge.first)
{
if (directed) current_edge.second = static_cast<SizeType>(0);
else current_edge.second = current_edge.first;
for (/* no init */; current_edge.second < n; ++current_edge.second) {
// When we hit the first edge, break out
if ((self_edges || current_edge.first != current_edge.second)
&& (*random_)() < p) {
return;
}
}
typedef uniform_int<vertices_size_type> distrib_t;
// Add random edges
edges_size_type edges_added = 0;
while (edges_added < num_vertices(g) * num_vertices(g) * edge_probability) {
vertex_iterator ui = vertices(g).first;
std::advance(ui, distrib_t(0, num_vertices(g)-1)(gen));
vertex_descriptor u = *ui;
vertex_descriptor v = vertex(distrib_t(0, n-1)(gen), g);
if ((u != v || allow_self_loops)
&& find(adjacent_vertices(u, g).first,
adjacent_vertices(u, g).second,
v) == adjacent_vertices(u, g).second) {
add_edge(u, v, g);
++edges_added;
}
}
// Past-the-end iterator
erdos_renyi_random_iterator(SizeType n) : n(n), current_edge(n, n) { }
private:
reference dereference() const { return current_edge; }
bool equal(const self_type& other) const
{ return current_edge == other.current_edge; }
void increment()
{
do {
if (++current_edge.second == n) {
if (++current_edge.first == n) break;
if (directed) current_edge.second = static_cast<SizeType>(0);
else current_edge.second = current_edge.first;
}
} while ((!self_edges && current_edge.first == current_edge.second)
|| (*random_)() >= p);
}
SizeType n;
Probability p;
shared_ptr<uniform_01<RandomGenerator, Probability> > random_;
bool directed : 1;
bool self_edges : 1;
value_type current_edge;
friend class iterator_core_access;
};
template<typename SizeType, typename Probability, typename RandomGenerator>
erdos_renyi_random_iterator<SizeType, Probability, RandomGenerator>
make_erdos_renyi_random_iterator(SizeType n, Probability p,
RandomGenerator& gen,
directed_tag,
bool self_edges = false)
{
typedef erdos_renyi_random_iterator<SizeType, Probability, RandomGenerator>
result_type;
return result_type(n, p, gen, true, self_edges);
// TBD: synchronize
}
template<typename SizeType, typename Probability, typename RandomGenerator>
erdos_renyi_random_iterator<SizeType, Probability, RandomGenerator>
make_erdos_renyi_random_iterator(SizeType n, Probability p,
RandomGenerator& gen,
undirected_tag,
bool self_edges = false)
template<typename MutableGraph, typename Real, typename RandomNumGen>
void
erdos_renyi_random_graph
(MutableGraph& g,
typename graph_traits<MutableGraph>::vertices_size_type n,
Real edge_probability,
bool allow_self_loops = false)
{
typedef erdos_renyi_random_iterator<SizeType, Probability, RandomGenerator>
result_type;
return result_type(n, p, gen, false, self_edges);
}
template<typename SizeType, typename Probability, typename RandomGenerator>
erdos_renyi_random_iterator<SizeType, Probability, RandomGenerator>
make_erdos_renyi_random_iterator(SizeType n, Probability, RandomGenerator&)
{
typedef erdos_renyi_random_iterator<SizeType, Probability, RandomGenerator>
result_type;
return result_type(n);
minstd_rand gen;
erdos_renyi_random_graph(g, n, edge_probability, allow_self_loops, gen);
}
}