void MainWindow::generateRouteReport()
{
int totalCost = 0;
QString route;
// Check a route actually exists
if (m_route.isEmpty() || !m_routeStart || !m_routeEnd) {
postErrorMessage("Route has not been built.");
return;
}
// Seed the route with the start node
route = m_routeStart->text();
// Iterate over the route list updating the variables above
QListIterator<EdgeItem*> i(m_route);
while (i.hasNext()) {
EdgeItem* edge = i.next();
// Add the target to the route
route += edge->endNode()->text();
// Update the cost
totalCost += edge->weight();
}
// Print the result
postInfoMessage(QString("Total route cost: %1").arg(totalCost));
postInfoMessage(QString("Route taken: %1").arg(route));
}
void MainWindow::routeNetwork()
{
// Storage class for the metadata required by Dijkstra
struct MetaData {
int distance;
EdgeItem* edge;
NodeItem* previous;
NodeItem* owner;
MetaData()
: distance(INT_MAX)
, edge(nullptr)
, previous(nullptr)
, owner(nullptr)
{
}
MetaData(NodeItem* owner_)
: distance(INT_MAX)
, edge(nullptr)
, previous(nullptr)
, owner(owner_)
{
}
};
QMap<NodeItem*, MetaData> metadata;
QList<NodeItem*> nodes;
NodeItem* current;
// Initialise data-structres
postInfoMessage("Preparing to route...");
{
QMapIterator<QString, NodeItem*> i(m_graphNodes);
while (i.hasNext()) {
auto item = i.next();
// Initialise the metadata
MetaData md(item.value());
if (item.value() == m_routeStart) {
// Need minimal distance for the start node
md.distance = 0;
}
metadata[i.value()] = md;
// Initialise the node list
nodes.append(i.value());
}
}
// Dijkstra's algorithm: calculate all the distances
while (!nodes.isEmpty()) {
// Find node with smallest distance
{
int d = INT_MAX;
auto elem = nodes.end();
for (auto it = nodes.begin(); it != nodes.end(); ++it) {
int thisDistance = metadata[*it].distance;
if (thisDistance < d) {
d = thisDistance;
elem = it;
}
}
current = *elem;
// If we hit the target, we can stop
if (current == m_routeEnd) {
postInfoMessage("Search complete; reached target node!");
break;
} else {
// Emshrinken the list
nodes.erase(elem);
}
}
postInfoMessage(QString("Considering node %1...")
.arg(current->text()));
// Visit the neighbours
QListIterator<EdgeItem*> i(current->edges());
while (i.hasNext()) {
EdgeItem* edge = i.next();
NodeItem* neighbour = edge->endNode();
int dist = metadata[current].distance + edge->weight();
if (dist < metadata[neighbour].distance) {
metadata[neighbour].distance = dist;
metadata[neighbour].edge = edge;
metadata[neighbour].previous = current;
}
}
}
// Walk backwards from the target to the source, building the path
postInfoMessage("Back-tracking to construct route...");
for (current = m_routeEnd; current; current = metadata[current].previous) {
EdgeItem* edge = metadata[current].edge;
if (edge) {
m_route.prepend(edge);
}
}
// All done!
postSuccessMessage("Routing complete!");
// Update the display
setHighlightStartNode(m_controlsDock->highlightStartNode());
setHighlightEndNode(m_controlsDock->highlightEndNode());
setHighlightPath(m_controlsDock->highlightPath());
}
