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Implement best first search #254

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merged 4 commits into from
Dec 23, 2022
Merged

Implement best first search #254

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f5df609
first implementation and tests
pradkrish Dec 21, 2022
1b2472f
add docs and minor changes
pradkrish Dec 22, 2022
3777e6a
minor change
pradkrish Dec 22, 2022
f79495e
minor change
pradkrish Dec 22, 2022
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75 changes: 75 additions & 0 deletions include/Graph/Graph.hpp
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Original file line number Diff line number Diff line change
Expand Up @@ -265,6 +265,7 @@ namespace CXXGRAPH
* search.
*
*/
virtual BestFirstSearchResult<T> best_first_search(const Node<T> &source, const Node<T> &target) const;
virtual const std::vector<Node<T>> breadth_first_search(const Node<T> &start) const;
/**
* \brief
Expand Down Expand Up @@ -1587,6 +1588,80 @@ namespace CXXGRAPH
return result;
}

template <typename T>
BestFirstSearchResult<T> Graph<T>::best_first_search(const Node<T> &source, const Node<T> &target) const
{
BestFirstSearchResult<T> result;
auto &nodeSet = Graph<T>::getNodeSet();
using pq_type = std::pair<double, const Node<T> *>;

if(std::find(nodeSet.begin(), nodeSet.end(), &source) == nodeSet.end())
{
result.errorMessage = ERR_SOURCE_NODE_NOT_IN_GRAPH;
return result;
}

if(std::find(nodeSet.begin(), nodeSet.end(), &target) == nodeSet.end())
{
result.errorMessage = ERR_TARGET_NODE_NOT_IN_GRAPH;
return result;
}

auto adj = Graph<T>::getAdjMatrix();
std::priority_queue<pq_type, std::vector<pq_type>, std::greater<pq_type>> pq;

std::vector<Node<T>> visited;
visited.push_back(source);
pq.push(std::make_pair(static_cast<T>(0), &source));

while (!pq.empty())
{
const Node<T> *currentNode = pq.top().second;
pq.pop();
result.nodesInBestSearchOrder.push_back(*currentNode);

if (*currentNode == target)
{
break;
}
if (adj.find(currentNode) != adj.end())
{
for (const auto &elem : adj.at(currentNode))
{
if (elem.second->isWeighted().has_value())
{
if (elem.second->isDirected().has_value())
{
const DirectedWeightedEdge<T> *dw_edge = static_cast<const DirectedWeightedEdge<T> *>(elem.second);
if (std::find(visited.begin(), visited.end(), *(elem.first)) == visited.end())
{
visited.push_back(*(elem.first));
pq.push(std::make_pair(dw_edge->getWeight(), elem.first));
}
}
else
{
const UndirectedWeightedEdge<T> *dw_edge = static_cast<const UndirectedWeightedEdge<T> *>(elem.second);
if (std::find(visited.begin(), visited.end(), *(elem.first)) == visited.end())
{
visited.push_back(*(elem.first));
pq.push(std::make_pair(dw_edge->getWeight(), elem.first));
}
}
}
else
{
result.errorMessage = ERR_NO_WEIGHTED_EDGE;
return result;
}
}
}
}

result.success = true;
return result;
}

template <typename T>
const std::vector<Node<T>> Graph<T>::breadth_first_search(const Node<T> &start) const
{
Expand Down
10 changes: 10 additions & 0 deletions include/Utility/Typedef.hpp
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Original file line number Diff line number Diff line change
Expand Up @@ -153,6 +153,16 @@ namespace CXXGRAPH
template <typename T>
using TopoSortResult = TopoSortResult_struct<T>;

template <typename T>
struct BestFirstSearchResult_struct
{
bool success = false;
std::string errorMessage = "";
std::vector<Node<T>> nodesInBestSearchOrder = {};
};
template <typename T>
using BestFirstSearchResult = BestFirstSearchResult_struct<T>;

/// Struct that contains the information about the partitioning statistics


Expand Down
136 changes: 136 additions & 0 deletions test/BestFirstSearchTest.cpp
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Original file line number Diff line number Diff line change
@@ -0,0 +1,136 @@
#include "gtest/gtest.h"
#include "CXXGraph.hpp"
#include <vector>

TEST(BestFirstSearchTest, source_node_missing)
{
CXXGRAPH::Node<int> node1("1", 1);
CXXGRAPH::Node<int> node2("2", 2);
CXXGRAPH::Node<int> node3("3", 3);
CXXGRAPH::Node<int> node4("4", 4);
std::pair<const CXXGRAPH::Node<int> *, const CXXGRAPH::Node<int> *> pairNode(&node1, &node2);
CXXGRAPH::DirectedWeightedEdge<int> edge1(1, pairNode, 1);
CXXGRAPH::DirectedWeightedEdge<int> edge2(2, node2, node3, 3);
CXXGRAPH::DirectedWeightedEdge<int> edge3(3, node1, node3, 6);
CXXGRAPH::T_EdgeSet<int> edgeSet;
edgeSet.insert(&edge1);
edgeSet.insert(&edge2);
edgeSet.insert(&edge3);
CXXGRAPH::Graph<int> graph(edgeSet);
CXXGRAPH::BestFirstSearchResult<int> && res = graph.best_first_search(node4, node1);
ASSERT_EQ(res.success, false);
ASSERT_EQ(res.nodesInBestSearchOrder.size(), 0);
ASSERT_EQ(res.errorMessage, CXXGRAPH::ERR_SOURCE_NODE_NOT_IN_GRAPH);
}

TEST(BestFirstSearchTest, target_node_missing)
{
CXXGRAPH::Node<int> node1("1", 1);
CXXGRAPH::Node<int> node2("2", 2);
CXXGRAPH::Node<int> node3("3", 3);
CXXGRAPH::Node<int> node4("4", 4);
std::pair<const CXXGRAPH::Node<int> *, const CXXGRAPH::Node<int> *> pairNode(&node1, &node2);
CXXGRAPH::DirectedWeightedEdge<int> edge1(1, pairNode, 1);
CXXGRAPH::DirectedWeightedEdge<int> edge2(2, node2, node3, 3);
CXXGRAPH::DirectedWeightedEdge<int> edge3(3, node1, node3, 6);
CXXGRAPH::T_EdgeSet<int> edgeSet;
edgeSet.insert(&edge1);
edgeSet.insert(&edge2);
edgeSet.insert(&edge3);
CXXGRAPH::Graph<int> graph(edgeSet);
CXXGRAPH::BestFirstSearchResult<int> && res = graph.best_first_search(node1, node4);
ASSERT_EQ(res.success, false);
ASSERT_EQ(res.nodesInBestSearchOrder.size(), 0);
ASSERT_EQ(res.errorMessage, CXXGRAPH::ERR_TARGET_NODE_NOT_IN_GRAPH);
}

TEST(BestFirstSearchTest, correct_example_small)
{
CXXGRAPH::Node<int> node1("1", 1);
CXXGRAPH::Node<int> node2("2", 2);
CXXGRAPH::Node<int> node3("3", 3);
std::pair<const CXXGRAPH::Node<int> *, const CXXGRAPH::Node<int> *> pairNode(&node1, &node2);
CXXGRAPH::DirectedWeightedEdge<int> edge1(1, pairNode, 1);
CXXGRAPH::DirectedWeightedEdge<int> edge2(2, node2, node3, 3);
CXXGRAPH::DirectedWeightedEdge<int> edge3(3, node1, node3, 6);
CXXGRAPH::T_EdgeSet<int> edgeSet;
edgeSet.insert(&edge1);
edgeSet.insert(&edge2);
edgeSet.insert(&edge3);
CXXGRAPH::Graph<int> graph(edgeSet);
CXXGRAPH::BestFirstSearchResult<int> && res = graph.best_first_search(node1, node2);
ASSERT_EQ(res.success, true);
ASSERT_EQ(res.nodesInBestSearchOrder.size(), 2);
ASSERT_EQ(res.errorMessage, "");
}

TEST(BestFirstSearchTest, source_target_same)
{
CXXGRAPH::Node<int> node1("1", 1);
CXXGRAPH::Node<int> node2("2", 2);
CXXGRAPH::Node<int> node3("3", 3);
std::pair<const CXXGRAPH::Node<int> *, const CXXGRAPH::Node<int> *> pairNode(&node1, &node2);
CXXGRAPH::DirectedWeightedEdge<int> edge1(1, pairNode, 1);
CXXGRAPH::DirectedWeightedEdge<int> edge2(2, node2, node3, 3);
CXXGRAPH::DirectedWeightedEdge<int> edge3(3, node1, node3, 6);
CXXGRAPH::T_EdgeSet<int> edgeSet;
edgeSet.insert(&edge1);
edgeSet.insert(&edge2);
edgeSet.insert(&edge3);
CXXGRAPH::Graph<int> graph(edgeSet);
CXXGRAPH::BestFirstSearchResult<int> && res = graph.best_first_search(node1, node1);
ASSERT_EQ(res.success, true);
ASSERT_EQ(res.nodesInBestSearchOrder.size(), 1);
ASSERT_EQ(res.errorMessage, "");
}

TEST(BestFirstSearchTest, correct_example_big)
{
CXXGRAPH::Node<int> node1("1", 1);
CXXGRAPH::Node<int> node2("2", 2);
CXXGRAPH::Node<int> node3("3", 3);
CXXGRAPH::Node<int> node4("4", 4);
CXXGRAPH::Node<int> node5("5", 5);
CXXGRAPH::Node<int> node6("6", 6);
CXXGRAPH::Node<int> node7("7", 7);
CXXGRAPH::Node<int> node8("8", 8);
CXXGRAPH::Node<int> node9("9", 9);
CXXGRAPH::Node<int> node10("10", 10);
CXXGRAPH::Node<int> node11("11", 11);
CXXGRAPH::Node<int> node12("12", 12);
CXXGRAPH::Node<int> node13("13", 13);
CXXGRAPH::Node<int> node14("14", 14);
std::pair<const CXXGRAPH::Node<int> *, const CXXGRAPH::Node<int> *> pairNode(&node1, &node2);
CXXGRAPH::DirectedWeightedEdge<int> edge1(1, node1, node2, 3);
CXXGRAPH::DirectedWeightedEdge<int> edge2(2, node1, node3, 6);
CXXGRAPH::DirectedWeightedEdge<int> edge3(3, node1, node4, 5);
CXXGRAPH::DirectedWeightedEdge<int> edge4(4, node2, node5, 9);
CXXGRAPH::DirectedWeightedEdge<int> edge5(5, node2, node6, 8);
CXXGRAPH::DirectedWeightedEdge<int> edge6(6, node3, node7, 12);
CXXGRAPH::DirectedWeightedEdge<int> edge7(7, node3, node8, 14);
CXXGRAPH::DirectedWeightedEdge<int> edge8(8, node4, node9, 7);
CXXGRAPH::DirectedWeightedEdge<int> edge9(9, node9, node10, 5);
CXXGRAPH::DirectedWeightedEdge<int> edge10(10, node9, node11, 6);
CXXGRAPH::DirectedWeightedEdge<int> edge11(10, node10, node12, 1);
CXXGRAPH::DirectedWeightedEdge<int> edge12(10, node10, node13, 10);
CXXGRAPH::DirectedWeightedEdge<int> edge13(10, node10, node14, 2);
CXXGRAPH::T_EdgeSet<int> edgeSet;
edgeSet.insert(&edge1);
edgeSet.insert(&edge2);
edgeSet.insert(&edge3);
edgeSet.insert(&edge4);
edgeSet.insert(&edge5);
edgeSet.insert(&edge6);
edgeSet.insert(&edge7);
edgeSet.insert(&edge8);
edgeSet.insert(&edge9);
edgeSet.insert(&edge10);
edgeSet.insert(&edge11);
edgeSet.insert(&edge12);
edgeSet.insert(&edge13);
CXXGRAPH::Graph<int> graph(edgeSet);
CXXGRAPH::BestFirstSearchResult<int> && res = graph.best_first_search(node1, node10);
ASSERT_EQ(res.success, true);
ASSERT_EQ(res.nodesInBestSearchOrder.size(), 6);
ASSERT_EQ(res.errorMessage, "");
}