NetPath VirtualLinkRouter::searchPathDejkstra(VirtualLink * virtualLink, Network * network, SearchPathAlgorithm algorithm)
{
if ( virtualLink->getFirst() == virtualLink->getSecond() )
return NetPath();
// local variables
std::set<ElementWeight, WeightCompare> elementsToParse;
std::map<Element * , Link*> incomingEdge;
std::map<Element * , std::vector<Link *> > elementLinks;
// initializing parameters
Links::iterator it = network->getLinks().begin();
Links::iterator itEnd = network->getLinks().end();
std::vector<Link *> * vecLinks = NULL;
for ( ; it != itEnd; ++it )
{
if ((*it)->getFirst() != virtualLink->getFirst()) elementsToParse.insert(ElementWeight((*it)->getFirst(), LONG_MAX)); // LONG_MAX equals to inf
if ((*it)->getSecond() != virtualLink->getFirst()) elementsToParse.insert(ElementWeight((*it)->getSecond(), LONG_MAX));
vecLinks = &elementLinks[(*it)->getFirst()];
if (vecLinks->capacity() < NLinks) vecLinks->reserve(NLinks);
vecLinks->push_back(*it);
vecLinks = &elementLinks[(*it)->getSecond()];
if (vecLinks->capacity() < NLinks) vecLinks->reserve(NLinks);
vecLinks->push_back(*it);
}
elementsToParse.insert(ElementWeight(virtualLink->getFirst(), 0));
elementsToParse.insert(ElementWeight(virtualLink->getSecond(), LONG_MAX));
Element * currentElement = virtualLink->getFirst();
Link edge("dijkstra edge", 0);
ElementWeight temp(NULL, -LONG_MAX);
std::set<ElementWeight, WeightCompare>::iterator tempIter;
long curWeight = 0;
// algorithm itself
while ( currentElement != NULL && currentElement != virtualLink->getSecond() )
{
temp.element = currentElement;
tempIter = elementsToParse.find(temp);
assert(tempIter != elementsToParse.end());
curWeight = tempIter->weight;
// std::cerr << "currentElement = " << currentElement << ", tempIter->element = " << tempIter->element << ", weight = " << tempIter->weight << '\n';
elementsToParse.erase(tempIter);
// going through all neighbors of current element,
// parsing their weight and choosing the element with the
// lowest weight
if ( elementLinks.find(currentElement) == elementLinks.end() )
{
return NetPath(); // No links assosiated with element
}
std::vector<Link *>& curLinks = elementLinks[currentElement];
unsigned int sz = curLinks.size();
for(unsigned int index = 0; index < sz; ++ index)
{
Link * cur = curLinks[index];
Element * other = cur->getFirst() == currentElement ?
cur->getSecond() : cur->getFirst();
temp.element = other;
temp.weight = LONG_MAX;
tempIter = elementsToParse.find(temp);
if ( tempIter != elementsToParse.end() )
{
edge.setCapacity(cur->getCapacity());
edge.bindElements(currentElement, other);
// weight of reaching the next element from current element
long weight = getEdgeWeigth(edge, network, algorithm) + curWeight;
if ( weight < tempIter->weight )
{
// have to erase and reinsert because weight is a part of the key
temp.element = other;
temp.weight = weight;
elementsToParse.erase(tempIter);
elementsToParse.insert(temp);
incomingEdge[other] = cur;
}
}
temp.weight = -LONG_MAX;
}
if (elementsToParse.begin()->weight != LONG_MAX) currentElement = elementsToParse.begin()->element;
else return NetPath(); // if an infinite weight is the minimum, it is a fail
}
if ( currentElement != virtualLink->getSecond() )
return NetPath(); // no way from one element to another
// retrieving the way
NetPath answer;
Element * other = currentElement; // for parsing results with just one edge
while ( incomingEdge[currentElement]->getFirst() != virtualLink->getFirst()
&& incomingEdge[currentElement]->getSecond() != virtualLink->getFirst() )
{
answer.push_back(incomingEdge[currentElement]);
other = incomingEdge[currentElement]->getFirst() == currentElement ?
incomingEdge[currentElement]->getSecond() : incomingEdge[currentElement]->getFirst();
answer.push_back(static_cast<NetworkingElement *>(other));
currentElement = other;
}
answer.push_back(incomingEdge[other]);
// this step may be skiped, but doing for sure
std::reverse(answer.begin(), answer.end());
return answer;
}
NetPath DijkstraRouter::search()
{
if ( !validateInput() )
{
printf("[RD]Wrong input\n");
return NetPath();
}
if ( link->getFirst() == link->getSecond() )
return NetPath();
std::set<ElementWeight, WeightCompare> elementsToParse;
std::map<Element * , Link *> incomingEdge;
std::map<Element * , std::vector<Link *> > elementLinks;
Links & links = network->getLinks();
for ( Links::iterator i = links.begin(); i != links.end(); i++ )
{
Link * l = *i;
if ( l->getFirst() != link->getFirst() )
elementsToParse.insert(ElementWeight(l->getFirst(), LONG_MAX));
if ( l->getSecond() != link->getFirst() )
elementsToParse.insert(ElementWeight(l->getSecond(), LONG_MAX));
elementLinks[l->getFirst()].push_back(l);
elementLinks[l->getSecond()].push_back(l);
}
elementsToParse.insert(ElementWeight(link->getFirst(), 0));
elementsToParse.insert(ElementWeight(link->getSecond(), LONG_MAX));
Element * currentElement = link->getFirst();
Link edge("dijkstraedge", 0);
ElementWeight temp(0, -LONG_MAX);
std::set<ElementWeight, WeightCompare>::iterator tempIter;
long curWeight = 0;
while ( currentElement != 0 && currentElement != link->getSecond() )
{
temp.element = currentElement;
tempIter = elementsToParse.find(temp);
assert(tempIter != elementsToParse.end());
curWeight = tempIter->weight;
elementsToParse.erase(tempIter);
if ( elementLinks.find(currentElement) == elementLinks.end() )
return NetPath();
std::vector<Link *>& curLinks = elementLinks[currentElement];
unsigned int size = curLinks.size();
for(unsigned int index = 0; index < size; index++)
{
Link * cur = curLinks[index];
Element * other = cur->getFirst() == currentElement ?
cur->getSecond() : cur->getFirst();
temp.element = other;
temp.weight = LONG_MAX;
tempIter = elementsToParse.find(temp);
if ( tempIter != elementsToParse.end() )
{
edge.setCapacity(cur->getCapacity());
edge.bindElements(currentElement, other);
long weight = getEdgeWeight(&edge) + curWeight;
if ( weight < tempIter->weight )
{
temp.element = other;
temp.weight = weight;
elementsToParse.erase(tempIter);
elementsToParse.insert(temp);
incomingEdge[other] = cur;
}
}
temp.weight = -LONG_MAX;
}
if (elementsToParse.begin()->weight != LONG_MAX)
currentElement = elementsToParse.begin()->element;
else
return NetPath();
}
if ( currentElement != link->getSecond() )
return NetPath();
Element * other = currentElement;
NetPath result;
while ( incomingEdge[currentElement]->getFirst() != link->getFirst()
&& incomingEdge[currentElement]->getSecond() != link->getFirst() )
{
result.push_back(incomingEdge[currentElement]);
other = incomingEdge[currentElement]->getFirst() == currentElement ?
incomingEdge[currentElement]->getSecond() : incomingEdge[currentElement]->getFirst();
result.push_back((NetworkingElement *)other);
currentElement = other;
}
result.push_back(incomingEdge[other]);
std::reverse(result.begin(), result.end());
return result;
}
