fn() dagShortestPathComputes shortest paths from a single source in a directed acyclic graph (DAG).
Computes shortest paths from a single source in a directed acyclic graph (DAG).
Defined in | <seqan/graph_algorithms.h> |
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Signature |
void dagShortestPath(predecessor, distance, g, source, weight);
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Parameters
predecessor
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A property map. A property map that represents predecessor relationships among vertices. It determines a shortest-paths tree. |
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distance
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A property map. Indicates for each vertex th distance from the source. do exist. |
g
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A directed acyclic graph. Types: Directed Graph |
source
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A source vertex. Types: VertexDescriptor |
weight
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A weight map. In a directed acyclic graph edge weights can be negative because no cycles |
Detailed Description
Example
#include <iostream> #include <seqan/graph_algorithms.h> using namespace seqan; int main() { typedef Graph<Directed<> > TGraph; typedef VertexDescriptor<TGraph>::Type TVertexDescriptor; typedef Size<TGraph>::Type TSize; // Create graph with 10 directed edges (0,2), (0,1), ... TSize numEdges = 10; TVertexDescriptor edges[] = {0, 2, 0, 1, 1, 3, 1, 2, 2, 5, 2, 4, 2, 3, 3, 5, 3, 4, 4, 5}; TGraph g; addEdges(g, edges, numEdges); // Print graph to stdout. std::cout << g << "\n"; // Create external edge property map with edge weights. int weights[] = {3, 5, 6, 2, 2, 4, 7, 1, -1, -2}; String<int> weightMap; assignEdgeMap(weightMap, g, weights); // Run DAG shortest path computation from vertex with descriptor 1. String<unsigned> predMap; String<unsigned> distMap; dagShortestPath(predMap, distMap, g, 1, weightMap); // Print result to stdout. std::cout << "Single-Source Shortest Paths in DAG: \n"; typedef Iterator<TGraph, VertexIterator>::Type TVertexIterator; TVertexIterator it(g); while (!atEnd(it)) { std::cout << "Path from 1 to " << getValue(it) << ": "; _printPath(g, predMap, (TVertexDescriptor)1, getValue(it)); std::cout << " (Distance: " << getProperty(distMap, getValue(it)) << ")\n"; goNext(it); } return 0; }
Adjacency list: 0 -> 1,2, 1 -> 2,3, 2 -> 3,4,5, 3 -> 4,5, 4 -> 5, 5 -> Edge list: Source: 0,Target: 1 (Id: 1) Source: 0,Target: 2 (Id: 0) Source: 1,Target: 2 (Id: 3) Source: 1,Target: 3 (Id: 2) Source: 2,Target: 3 (Id: 6) Source: 2,Target: 4 (Id: 5) Source: 2,Target: 5 (Id: 4) Source: 3,Target: 4 (Id: 8) Source: 3,Target: 5 (Id: 7) Source: 4,Target: 5 (Id: 9) Single-Source Shortest Paths in DAG: Path from 1 to 0: No path from 1 to 0 exists. (Distance: 1073741823) Path from 1 to 1: 1 (Distance: 0) Path from 1 to 2: 1,2 (Distance: 2) Path from 1 to 3: 1,3 (Distance: 6) Path from 1 to 4: 1,3,4 (Distance: 5) Path from 1 to 5: 1,3,4,5 (Distance: 3)
Data Races
Thread safety unknown!