From 186d6baaaa07504c3cdafb3623af4d17e2e68330 Mon Sep 17 00:00:00 2001
From: Jeremiah Willcock <jewillco@osl.iu.edu>
Date: Tue, 26 May 2009 15:42:40 +0000
Subject: [PATCH] Added no-color-map version of Dijkstra's algorithm from
 Michael Hansen

[SVN r53282]
---
 .../dijkstra_shortest_paths_no_color_map.hpp  | 147 ++++++++++++++++++
 1 file changed, 147 insertions(+)
 create mode 100644 include/boost/graph/dijkstra_shortest_paths_no_color_map.hpp

diff --git a/include/boost/graph/dijkstra_shortest_paths_no_color_map.hpp b/include/boost/graph/dijkstra_shortest_paths_no_color_map.hpp
new file mode 100644
index 00000000..268a70b9
--- /dev/null
+++ b/include/boost/graph/dijkstra_shortest_paths_no_color_map.hpp
@@ -0,0 +1,147 @@
+//=======================================================================
+// Copyright 1997, 1998, 1999, 2000 University of Notre Dame.
+// Copyright 2009 Trustees of Indiana University.
+// Authors: Andrew Lumsdaine, Lie-Quan Lee, Jeremy G. Siek, Michael Hansen
+//
+// Distributed under the Boost Software License, Version 1.0. (See
+// accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt)
+//=======================================================================
+
+#ifndef BOOST_GRAPH_DIJKSTRA_NO_COLOR_MAP_HPP
+#define BOOST_GRAPH_DIJKSTRA_NO_COLOR_MAP_HPP
+
+#include <boost/pending/indirect_cmp.hpp>
+#include <boost/graph/relax.hpp>
+#include <boost/pending/relaxed_heap.hpp>
+#include <boost/graph/detail/d_ary_heap.hpp>
+#include <boost/graph/dijkstra_shortest_paths.hpp>
+#include <boost/graph/iteration_macros.hpp>
+
+namespace boost {
+
+template <typename Graph, typename DijkstraVisitor,
+          typename PredecessorMap, typename DistanceMap,
+          typename WeightMap, typename VertexIndexMap,
+          typename DistanceCompare, typename DistanceWeightCombine,
+          typename DistanceInfinity, typename DistanceZero>
+void dijkstra_shortest_paths_no_color_map
+  (const Graph& graph,
+   typename graph_traits<Graph>::vertex_descriptor start_vertex,
+   PredecessorMap predecessor_map,
+   DistanceMap distance_map,
+   WeightMap weight_map,
+   VertexIndexMap vertex_index_map,
+   DistanceCompare distance_compare,
+   DistanceWeightCombine distance_weight_combine,
+   DistanceInfinity distance_infinity,
+   DistanceZero distance_zero,
+   DijkstraVisitor visitor)
+{
+  typedef typename graph_traits<Graph>::vertex_descriptor Vertex;
+  typedef typename property_traits<DistanceMap>::value_type Distance;
+  typedef typename property_traits<WeightMap>::value_type Weight;
+  
+  typedef indirect_cmp<DistanceMap, DistanceCompare> DistanceIndirectCompare;
+  DistanceIndirectCompare
+    distance_indirect_compare(distance_map, distance_compare);
+
+  // Choose vertex queue type
+#if BOOST_GRAPH_DIJKSTRA_USE_RELAXED_HEAP
+  typedef relaxed_heap<Vertex, DistanceIndirectCompare, VertexIndexMap>
+    VertexQueue;
+  VertexQueue vertex_queue(num_vertices(graph),
+                           distance_indirect_compare,
+                           vertex_index_map);
+#else
+  // Default - use d-ary heap (d = 4)
+  typedef
+    detail::vertex_property_map_generator<Graph, VertexIndexMap, std::size_t>
+    IndexInHeapMapHelper;
+  typedef typename IndexInHeapMapHelper::type IndexInHeapMap;
+  typedef
+    d_ary_heap_indirect<Vertex, 4, IndexInHeapMap, DistanceMap, DistanceCompare>
+    VertexQueue;
+
+  boost::scoped_array<std::size_t> index_in_heap_map_holder;
+  IndexInHeapMap index_in_heap =
+    IndexInHeapMapHelper::build(graph, vertex_index_map,
+                                index_in_heap_map_holder);  
+  VertexQueue vertex_queue(distance_map, index_in_heap, distance_compare);
+#endif
+
+  // Initialize vertices
+  BGL_FORALL_VERTICES_T(current_vertex, graph, Graph) {
+    visitor.initialize_vertex(current_vertex, graph);
+    
+    // Default all distances to infinity
+    put(distance_map, current_vertex, distance_infinity);
+
+    // Default all vertex predecessors to the vertex itself
+    put(predecessor_map, current_vertex, current_vertex);
+  }
+
+  // Set distance for start_vertex to zero
+  put(distance_map, start_vertex, distance_zero);
+
+  // Add vertex to the queue
+  vertex_queue.push(start_vertex);
+
+  // Starting vertex will always be the first discovered vertex
+  visitor.discover_vertex(start_vertex, graph);
+
+  while (!vertex_queue.empty()) {
+    Vertex min_vertex = vertex_queue.top();
+    vertex_queue.pop();
+    
+    visitor.examine_vertex(min_vertex, graph);
+
+    // Check if any other vertices can be reached
+    Distance min_vertex_distance = get(distance_map, min_vertex);
+    
+    if (!distance_compare(min_vertex_distance, distance_infinity)) {
+      // This is the minimum vertex, so all other vertices are unreachable
+      return;
+    }
+
+    // Examine neighbors of min_vertex
+    typedef typename graph_traits<Graph>::edge_descriptor Edge;
+    typename graph_traits<Graph>::out_edge_iterator edge_iter, edge_iter_end;
+    BGL_FORALL_OUT_EDGES_T(current_edge, min_vertex, graph, Graph) {
+      visitor.examine_edge(current_edge, graph);
+      
+      // Check if the edge has a negative weight
+      if (distance_compare(get(weight_map, current_edge), distance_zero)) {
+        boost::throw_exception(negative_edge());
+      }
+      
+      Vertex neighbor_vertex = target(current_edge, graph);
+      Distance neighbor_vertex_distance = get(distance_map, neighbor_vertex);
+      bool is_neighbor_undiscovered = 
+        !distance_compare(neighbor_vertex_distance, distance_infinity);
+
+      // Attempt to relax the edge
+      bool was_edge_relaxed = relax(current_edge, graph, weight_map,
+        predecessor_map, distance_map,
+        distance_weight_combine, distance_compare);
+
+      if (was_edge_relaxed) {
+        vertex_queue.update(neighbor_vertex);
+        visitor.edge_relaxed(current_edge, graph);
+      } else {
+        visitor.edge_not_relaxed(current_edge, graph);
+      }
+
+      if (is_neighbor_undiscovered) {
+        visitor.discover_vertex(neighbor_vertex, graph);
+        vertex_queue.push(neighbor_vertex);
+      }
+    } // end out edge iteration
+
+    visitor.finish_vertex(min_vertex, graph);
+  } // end while queue not empty
+}
+
+} // namespace boost
+
+#endif // BOOST_GRAPH_DIJKSTRA_NO_COLOR_MAP_HPP