mage/cpp/algo_module/algorithm/algo.cpp at main · memgraph/mage · GitHub

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#include "algo.hpp"

#include "mgp.hpp"

Algo::PathFinder::PathFinder(const mgp::Node &start_node, const mgp::Node &end_node, int64_t max_length,

const mgp::List &rel_types, const mgp::RecordFactory &record_factory)

: start_node_(start_node), end_node_id_(end_node.Id()), max_length_(max_length), record_factory_(record_factory) {

UpdateRelationshipDirection(rel_types);

}

void Algo::PathFinder::UpdateRelationshipDirection(const mgp::List &relationship_types) {

all_incoming_ = false;

all_outgoing_ = false;

if (relationship_types.Size() == 0) { // if no relationships were passed as arguments, all relationships are allowed

any_outgoing_ = true;

any_incoming_ = true;

return;

}

bool in_rel = false;

bool out_rel = false;

for (const auto &rel : relationship_types) {

std::string rel_type{std::string(rel.ValueString())};

bool starts_with = rel_type.starts_with('<');

bool ends_with = rel_type.ends_with('>');

// '<' -> all incoming relationship are accepted

// '>' -> all outgoing relationships are good

if (rel_type.size() == 1) {

if (starts_with) {

any_incoming_ = true;

in_rel = true;

} else if (ends_with) {

any_outgoing_ = true;

out_rel = true;

} else {

rel_direction_[rel_type] = RelDirection::kAny;

in_rel = out_rel = true;

}

continue;

}

if (starts_with && ends_with) { // <type>

rel_direction_[rel_type.substr(1, rel_type.size() - 2)] = RelDirection::kBoth;

in_rel = out_rel = true;

} else if (starts_with) { // <type

rel_direction_[rel_type.substr(1)] = RelDirection::kIncoming;

in_rel = true;

} else if (ends_with) { // type>

rel_direction_[rel_type.substr(0, rel_type.size() - 1)] = RelDirection::kOutgoing;

out_rel = true;

} else { // type

rel_direction_[rel_type] = RelDirection::kAny;

in_rel = out_rel = true;

}

if (!in_rel) {

all_outgoing_ = true;

} else if (!out_rel) {

all_incoming_ = true;

}

Algo::RelDirection Algo::PathFinder::GetDirection(const std::string &rel_type) const {

auto it = rel_direction_.find(rel_type);

if (it == rel_direction_.end()) {

return RelDirection::kNone;

}

return it->second;

}

void Algo::PathFinder::DFS(const mgp::Node &curr_node, mgp::Path &curr_path, std::unordered_set<int64_t> &visited) {

if (curr_node.Id() == end_node_id_) {

auto record = record_factory_.NewRecord();

record.Insert(std::string(kResultAllSimplePaths).c_str(), curr_path);

return;

}

if (static_cast<int64_t>(curr_path.Length()) == max_length_) {

return;

}

visited.insert(curr_node.Id().AsInt());

std::unordered_set<int64_t> seen;

auto iterate = [&visited, &seen, &curr_path, this](mgp::Relationships relationships, RelDirection direction,

bool always_expand) {

for (const auto relationship : relationships) {

auto next_node_id =

direction == RelDirection::kOutgoing ? relationship.To().Id().AsInt() : relationship.From().Id().AsInt();

if (visited.contains(next_node_id)) {

continue;

}

auto type = std::string(relationship.Type());

auto wanted_direction = GetDirection(type);

if (always_expand || wanted_direction == RelDirection::kAny || wanted_direction == direction) {

curr_path.Expand(relationship);

DFS(direction == RelDirection::kOutgoing ? relationship.To() : relationship.From(), curr_path, visited);

curr_path.Pop();

} else if (wanted_direction == RelDirection::kBoth) {

if (direction == RelDirection::kOutgoing && seen.contains(relationship.To().Id().AsInt())) {

curr_path.Expand(relationship);

DFS(relationship.To(), curr_path, visited);

curr_path.Pop();

} else if (direction == RelDirection::kIncoming) {

seen.insert(relationship.From().Id().AsInt());

}

};

if (!all_outgoing_) {

iterate(curr_node.InRelationships(), RelDirection::kIncoming, any_incoming_);

}

if (!all_incoming_) {

iterate(curr_node.OutRelationships(), RelDirection::kOutgoing, any_outgoing_);

}

visited.erase(curr_node.Id().AsInt());

}

void Algo::PathFinder::FindAllPaths() {

mgp::Path path{start_node_};

std::unordered_set<int64_t> visited;

DFS(start_node_, path, visited);

}

void Algo::AllSimplePaths(mgp_list *args, mgp_graph *memgraph_graph, mgp_result *result, mgp_memory *memory) {

mgp::MemoryDispatcherGuard guard{memory};

const auto arguments = mgp::List(args);

const auto record_factory = mgp::RecordFactory(result);

try {

const auto start_node{arguments[0].ValueNode()};

const auto end_node{arguments[1].ValueNode()};

const auto rel_types{arguments[2].ValueList()};

const auto max_nodes{arguments[3].ValueInt()};

PathFinder pathfinder{start_node, end_node, max_nodes, rel_types, record_factory};

pathfinder.FindAllPaths();

} catch (const std::exception &e) {

record_factory.SetErrorMessage(e.what());

return;

}

void Algo::Cover(mgp_list *args, mgp_graph *memgraph_graph, mgp_result *result, mgp_memory *memory) {

mgp::MemoryDispatcherGuard guard{memory};

const auto arguments = mgp::List(args);

const auto record_factory = mgp::RecordFactory(result);

try {

auto list_nodes = arguments[0].ValueList();

std::unordered_set<mgp::Node> nodes;

for (const auto &elem : list_nodes) {

auto node = elem.ValueNode();

nodes.insert(node);

}

for (const auto &node : nodes) {

for (const auto rel : node.OutRelationships()) {

if (nodes.find(rel.To()) != nodes.end()) {

auto record = record_factory.NewRecord();

record.Insert(std::string(kCoverRet1).c_str(), rel);

}

} catch (const std::exception &e) {

record_factory.SetErrorMessage(e.what());

return;

}

void Algo::CheckConfigTypes(const mgp::Map &map) {

if (!map.At("unweighted").IsNull() && !map.At("unweighted").IsBool()) {

throw mgp::ValueException("unweighted config option should be bool!");

}

if (!map.At("epsilon").IsNull() && !map.At("epsilon").IsNumeric()) {

throw mgp::ValueException("epsilon config option should be numeric!");

}

if (!map.At("distance_prop").IsNull() && !map.At("distance_prop").IsString()) {

throw mgp::ValueException("distance_prop config option should be string!");

}

if (!map.At("heuristic_name").IsNull() && !map.At("heuristic_name").IsString()) {

throw mgp::ValueException("heuristic_name config option should be string!");

}

if (!map.At("latitude_name").IsNull() && !map.At("latitude_name").IsString()) {

throw mgp::ValueException("latitude_name config option should be string!");

}

if (!map.At("longitude_name").IsNull() && !map.At("longitude_name").IsString()) {

throw mgp::ValueException("longitude_name config option should be string!");

}

if (!map.At("whitelisted_labels").IsNull() && !map.At("whitelisted_labels").IsList()) {

throw mgp::ValueException("whitelisted_labels config option should be list!");

}

if (!map.At("whitelisted_labels").IsNull()) {

auto list = map.At("whitelisted_labels").ValueList();

for (const auto value : list) {

if (!value.IsString()) {

throw mgp::ValueException("Labels in the whitelisted_labels config list must be strings!");

}

if (!map.At("blacklisted_labels").IsNull() && !map.At("blacklisted_labels").IsList()) {

throw mgp::ValueException("blacklisted_labels config option should be list!");

}

if (!map.At("blacklisted_labels").IsNull()) {

auto list = map.At("blacklisted_labels").ValueList();

for (const auto value : list) {

if (!value.IsString()) {

throw mgp::ValueException("Labels in the blacklisted_labels config list must be strings!");

}

if (!map.At("relationships_filter").IsNull() && !map.At("relationships_filter").IsList()) {

throw mgp::ValueException("relationships_filter config option should be list!");

} else if (!map.At("relationships_filter").IsNull() && map.At("relationships_filter").IsList()) {

auto list = map.At("relationships_filter").ValueList();

for (const auto value : list) {

if (!value.IsString()) {

throw mgp::ValueException("Elements in relationships_filter config list must be strings!");

}

auto rel_type = std::string(value.ValueString());

const size_t size = rel_type.size();

const char first_elem = rel_type[0];

const char last_elem = rel_type[size - 1];

if (first_elem == '<' && last_elem == '>') {

throw mgp::ValueException("Wrong relationship format => <relationship> is not allowed!");

}

if (!map.At("duration").IsNull() && !map.At("duration").IsBool()) {

throw mgp::ValueException("duration config option should be bool!");

}

double Algo::GetRadians(double degrees) { return degrees * M_PI / 180.0; }

double Algo::GetHaversineDistance(double lat1, double lon1, double lat2, double lon2) {

// IN KM

const double earthRadius = 6371.0;

lat1 = GetRadians(lat1);

lon1 = GetRadians(lon1);

lat2 = GetRadians(lat2);

lon2 = GetRadians(lon2);

double dLat = lat2 - lat1;

double dLon = lon2 - lon1;

double a = sin(dLat / 2) * sin(dLat / 2) + cos(lat1) * cos(lat2) * sin(dLon / 2) * sin(dLon / 2);

double c = 2 * atan2(sqrt(a), sqrt(1 - a));

double distance = earthRadius * c;

// returns distance in km

return distance;

}

// calculates the heuristic based on haversine, or returns the value if the heuristic is custom

double Algo::CalculateHeuristic(const Config &config, const mgp::Node &node, const GoalNodes &nodes) {

if (config.heuristic_name != kDefaultHeuristic) {

auto heuristic = node.GetProperty(config.heuristic_name);

if (heuristic.IsNumeric()) {

return heuristic.ValueNumeric();

}

if (heuristic.IsDuration() && config.duration) {

return heuristic.ValueDuration().Microseconds();

}

throw mgp::ValueException("Custom heuristic property must be of a numeric, or duration data type!");

}

auto coordinate_pair = GetLatLon(node, config);

auto &latitude_source = coordinate_pair.first;

auto &longitude_source = coordinate_pair.second;

return GetHaversineDistance(latitude_source, longitude_source, nodes.lat_lon.first, nodes.lat_lon.second);

}

std::pair<double, double> Algo::GetLatLon(const mgp::Node &target, const Config &config) {

auto latitude = target.GetProperty(config.latitude_name);

auto longitude = target.GetProperty(config.latitude_name);

if (latitude.IsNull() || longitude.IsNull()) {

throw mgp::ValueException(

"Latitude and longitude properties, or a custom heuristic value, must be specified in every node!");

}

if (latitude.IsNumeric() && longitude.IsNumeric()) {

return std::make_pair<double, double>(latitude.ValueNumeric(), longitude.ValueNumeric());

}

throw mgp::ValueException("Latitude and longitude must be numeric data types!");

}

double Algo::CalculateDistance(const Config &config, const mgp::Relationship &rel) {

if (config.unweighted) { // return same distance if unweighted

return 10;

}

auto distance = rel.GetProperty(config.distance_prop);

if (distance.IsNull()) {

throw mgp::ValueException("If the graph is weighted, distance property of the relationship must be specified!");

}

if (distance.IsNumeric()) {

return distance.ValueNumeric();

}

if (distance.IsDuration() && config.duration) {

return distance.ValueDuration().Microseconds();

}

throw mgp::ValueException("Distance property must be a numeric or duration datatype!");

}

bool Algo::RelOk(const mgp::Relationship &rel, const Config &config,

const RelationshipType rel_type) { // in true incoming, in false outgoing

if (config.in_rels.size() == 0 && config.out_rels.size() == 0) {

return true;

}

if (rel_type == RelationshipType::IN && config.in_rels.find(std::string(rel.Type())) != config.in_rels.end()) {

return true;

}

if (rel_type == RelationshipType::OUT && config.out_rels.find(std::string(rel.Type())) != config.out_rels.end()) {

return true;

}

return false;

}

bool Algo::IsLabelOk(const mgp::Node &node, const Config &config) {

bool whitelist_empty = config.whitelist.empty();

for (auto label : node.Labels()) {

if (config.blacklist.find(std::string(label)) != config.blacklist.end()) {

return false;

}

if (!whitelist_empty && config.whitelist.find(std::string(label)) == config.whitelist.end()) {

return false;

}

return true;

}

void Algo::ExpandRelationships(const std::shared_ptr<NodeObject> &prev, const RelationshipType rel_type,

const GoalNodes &nodes, TrackingLists &lists, const Config &config) {

auto rels = rel_type == RelationshipType::IN ? prev->node.InRelationships() : prev->node.OutRelationships();

for (const auto rel : rels) {

if (!RelOk(rel, config, rel_type)) {

continue;

}

const auto node = rel_type == RelationshipType::IN ? rel.From() : rel.To();

if (!IsLabelOk(node, config)) {

continue;

}

auto heuristic = CalculateHeuristic(config, node, nodes) * config.epsilon; // epsilon 0 == UCS

auto distance = CalculateDistance(config, rel);

auto nb = std::make_shared<NodeObject>(heuristic, distance + prev->total_distance, node, rel, prev);

if (!lists.closed.FindAndCompare(nb)) {

continue;

}

lists.open.InsertOrUpdate(nb);

}

std::shared_ptr<Algo::NodeObject> Algo::InitializeStart(const mgp::Node &start) {

if (start.InDegree() == 0 && start.OutDegree() == 0) {

throw mgp::ValueException("Start node must have in or out relationships!");

}

if (start.InDegree() != 0) {

return std::make_shared<NodeObject>(0, 0, start, *start.InRelationships().begin(), nullptr);

}

return std::make_shared<NodeObject>(0, 0, start, *start.OutRelationships().begin(), nullptr);

}

std::pair<mgp::Path, double> Algo::HelperAstar(const GoalNodes &nodes, const Config &config) {

TrackingLists lists = TrackingLists();

auto start_nb = InitializeStart(nodes.start);

lists.open.InsertOrUpdate(start_nb);

while (!lists.open.Empty()) {

auto nb = lists.open.Top();

lists.open.Pop();

if (nb->node == nodes.target) {

return BuildResult(nb, nodes.start);

}

lists.closed.Insert(nb);

ExpandRelationships(nb, RelationshipType::OUT, nodes, lists, config);

ExpandRelationships(nb, RelationshipType::IN, nodes, lists, config);

}

return std::pair<mgp::Path, double>(mgp::Path(nodes.start), 0);

}

std::pair<mgp::Path, double> Algo::BuildResult(std::shared_ptr<NodeObject> final_node, const mgp::Node &start) {

mgp::Path path = mgp::Path(start);

std::vector<mgp::Relationship> rels;

double weight = final_node->total_distance;

while (final_node->prev) {

rels.push_back(final_node->rel);

final_node = final_node->prev;

}

for (auto it = rels.rbegin(); it != rels.rend(); ++it) {

path.Expand(std::move(*it));

}

return std::pair<mgp::Path, double>(std::move(path), weight);

}

void Algo::AStar(mgp_list *args, mgp_graph *memgraph_graph, mgp_result *result, mgp_memory *memory) {

mgp::MemoryDispatcherGuard guard{memory};

const auto arguments = mgp::List(args);

const auto record_factory = mgp::RecordFactory(result);

try {

auto start = arguments[0].ValueNode();

auto target = arguments[1].ValueNode();

auto config_map = arguments[2].ValueMap();

CheckConfigTypes(config_map);

auto config = Config(config_map);

// if there is a custom heuristic, there is no need for target latitude and lognitude

auto nodes = config.heuristic_name == kDefaultHeuristic ? GoalNodes(start, target, GetLatLon(target, config))

: GoalNodes(start, target);

std::pair<mgp::Path, double> pair = HelperAstar(nodes, config);

mgp::Path &path = pair.first;

const double weight = pair.second;

auto record = record_factory.NewRecord();

record.Insert(std::string(kAStarPath).c_str(), std::move(path));

record.Insert(std::string(kAStarWeight).c_str(), weight);

} catch (const std::exception &e) {

record_factory.SetErrorMessage(e.what());

return;

}

mage/cpp/algo_module/algorithm/algo.cpp at main · memgraph/mage · GitHub

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