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  1. #include <iostream>
  2. #include <iomanip>
  3.  
  4. #include <boost/graph/grid_graph.hpp>
  5. #include <boost/graph/detail/d_ary_heap.hpp>
  6. #include <boost/property_map/property_map.hpp>
  7.  
  8. #include <cstdlib>
  9.  
  10. template <typename TGraph, typename TIndexInHeapMap>
  11. static void OutputIndexHeapMap(TGraph g, TIndexInHeapMap indexHeapMap);
  12.  
  13. int main(int, char*[])
  14. {
  15.   // Seed random number gererators
  16.   srand((unsigned int)time(NULL));
  17.   srand48((unsigned int)time(NULL));
  18.  
  19.   // Create a graph
  20.   boost::array<std::size_t, 2> lengths = { { 2,2 } };
  21.   typedef boost::grid_graph<2> GraphType;
  22.   GraphType graph(lengths);
  23.  
  24.   // Declare iterators that we will use
  25.   typedef boost::graph_traits<GraphType>::vertex_iterator VertexIteratorType;
  26.  
  27.   VertexIteratorType vertexIterator, vertexIteratorEnd;
  28.  
  29.   // Setup the graph properties
  30.   typedef boost::graph_traits<GraphType>::vertex_descriptor Vertex;
  31.   typedef boost::property_map<GraphType, boost::vertex_index_t>::const_type GridIndexMapType;
  32.   GridIndexMapType gridIndexMap(get(boost::vertex_index, graph));
  33.  
  34.   typedef boost::vector_property_map<std::size_t, GridIndexMapType> IndexInHeapMap;
  35.   IndexInHeapMap index_in_heap(gridIndexMap);
  36.  
  37.   // Initialize
  38.   for( tie(vertexIterator, vertexIteratorEnd) = vertices(graph); vertexIterator != vertexIteratorEnd; ++vertexIterator)
  39.   {
  40.     put(index_in_heap, *vertexIterator, (size_t)(-1));
  41.   }
  42.  
  43.   std::cout << "Initial heap map" << std::endl;
  44.   OutputIndexHeapMap(graph, index_in_heap);
  45.  
  46.   typedef boost::vector_property_map<float, GridIndexMapType> PriorityMapType;
  47.   PriorityMapType priorityMap(gridIndexMap);
  48.  
  49.   // Setup the queue
  50.   typedef std::greater<float> ComparisonFunctor;
  51.   typedef boost::d_ary_heap_indirect<Vertex, 4, IndexInHeapMap,
  52.       PriorityMapType, ComparisonFunctor > MutableQueueType;
  53.  
  54.   ComparisonFunctor comparisonFunctor;
  55.   MutableQueueType mutableQueue(priorityMap, index_in_heap, comparisonFunctor);
  56.  
  57.   std::cout << "There are " << mutableQueue.size() << " items in the queue." << std::endl;
  58.  
  59.   // Add random values to the vertices and add them to the queue
  60.   for( tie(vertexIterator, vertexIteratorEnd) = vertices(graph); vertexIterator != vertexIteratorEnd; ++vertexIterator)
  61.   {
  62.     float newPriority = rand() % 1000;
  63.     Vertex v = *vertexIterator;
  64.  
  65.     std::cout << "Original priority for " << v[0] << ", " << v[1] << " " << newPriority << std::endl;
  66.     put(priorityMap, *vertexIterator, newPriority);
  67.     mutableQueue.push(*vertexIterator);
  68.   }
  69.  
  70.   std::cout << "Heap map after initial pushes:" << std::endl;
  71.   OutputIndexHeapMap(graph, index_in_heap);
  72.  
  73.   std::cout << "There are " << mutableQueue.size() << " items in the queue." << std::endl;
  74.  
  75.   // Insert another set of random values for each vertex
  76.   for( tie(vertexIterator, vertexIteratorEnd) = vertices(graph); vertexIterator != vertexIteratorEnd; ++vertexIterator)
  77.   {
  78.     float newPriority = rand() % 1000;
  79.  
  80.     Vertex v = *vertexIterator;
  81.     std::cout << "New priority for " << v[0] << ", " << v[1] << " " << newPriority << std::endl;
  82.     put(priorityMap, *vertexIterator, newPriority);
  83.     mutableQueue.update(*vertexIterator);
  84.   }
  85.  
  86.   std::cout << "Heap map after updates:" << std::endl;
  87.   OutputIndexHeapMap(graph, index_in_heap);
  88.  
  89.   std::cout << "There are " << mutableQueue.size() << " items in the queue." << std::endl;
  90.  
  91.   // Output (and empty) the queue
  92.   while( ! mutableQueue.empty() )
  93.   {
  94. //    MutableQueueType::value_type u = mutableQueue.top();
  95.     Vertex u = mutableQueue.top();
  96.  
  97.     // These two lines are equivalent
  98.     std::cout << "vertex: " << u[0] << " " << u[1]
  99.               << " priority: " << get(mutableQueue.keys(), u)
  100.               << std::endl;
  101.  
  102.     mutableQueue.pop();
  103.   }
  104.  
  105.   std::cout << "Heap map at end:" << std::endl; // All (size_t)(-1)
  106.   OutputIndexHeapMap(graph, index_in_heap);
  107.  
  108.   std::cout << std::endl;
  109.  
  110.   return 0;
  111. }
  112.  
  113. template <typename TGraph, typename TIndexInHeapMap>
  114. static void OutputIndexHeapMap(TGraph g, TIndexInHeapMap indexHeapMap)
  115. {
  116.   typedef typename boost::graph_traits<TGraph>::vertex_iterator VertexIteratorType;
  117.   VertexIteratorType vertexIterator, vertexIteratorEnd;
  118.   for( tie(vertexIterator, vertexIteratorEnd) = vertices(g); vertexIterator != vertexIteratorEnd; ++vertexIterator)
  119.   {
  120.     std::cout << "Index: " << get(indexHeapMap, *vertexIterator) << std::endl;
  121.   }
  122. }
  123.  
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https://ideone.com/cZosV
language:
C++ (gcc 8.3)
created:
12 years ago
visibility:
public

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