/// <summary>
/// Select the next vertex from the queue.
/// </summary>
/// <returns></returns>
private uint?SelectNext()
{
// first check the first of the current queue.
while (_queue.Count > 0)
{ // get the first vertex and check.
// TODO: peek and get the weight at the same time.
uint first_queued = _queue.Peek();
// the lazy updating part!
// calculate priority
float priority = _calculator.Calculate(first_queued);
float current_priority = _queue.Weight(first_queued);
if (priority != current_priority)
{ // a succesfull update.
_misses_queue.Enqueue(true);
_misses++;
}
else
{ // an unsuccessfull update.
_misses_queue.Enqueue(false);
}
if (_misses_queue.Count > _k)
{ // dequeue and update the misses.
if (_misses_queue.Dequeue())
{
_misses--;
}
}
// if the misses are _k
if (_misses == _k)
{ // recalculation.
CHPriorityQueue new_queue = new CHPriorityQueue();
HashSet <KeyValuePair <uint, float> > recalculated_weights =
new HashSet <KeyValuePair <uint, float> >();
foreach (uint vertex in _queue)
{
recalculated_weights.Add(
new KeyValuePair <uint, float>(vertex, _calculator.Calculate(vertex)));
}
foreach (KeyValuePair <uint, float> pair in recalculated_weights)
{
new_queue.Enqueue(pair.Key, pair.Value);
}
_queue = new_queue;
_misses_queue.Clear();
_misses = 0;
}
else
{ // no recalculation.
if (priority > current_priority)
{ // re-enqueue the weight.
_queue.Enqueue(first_queued, priority);
}
else
{
//if (this.CanBeContracted(first_queued))
//{ // yet, this vertex can be contracted!
_queue.Remove(first_queued);
return(first_queued);
}
}
}
// check the queue.
if (_queue.Count > 0)
{
throw new Exception("Unqueued items left!, CanBeContracted is too restrictive!");
}
return(null); // all nodes have been contracted.
}
/// <summary>
/// Select the next vertex from the queue.
/// </summary>
/// <returns></returns>
private uint?SelectNext()
{
// first check the first of the current queue.
while (_queue.Count > 0)
{ // get the first vertex and check.
// TODO: peek and get the weight at the same time.
uint first_queued = _queue.Peek();
// the lazy updating part!
// calculate priority
float priority = _calculator.Calculate(first_queued);
float current_priority = _queue.Weight(first_queued);
if (priority != current_priority)
{ // a succesfull update.
_missesQueue.Enqueue(true);
_misses++;
}
else
{ // an unsuccessfull update.
_missesQueue.Enqueue(false);
}
if (_missesQueue.Count > _k)
{ // dequeue and update the misses.
if (_missesQueue.Dequeue())
{
_misses--;
}
}
// if the misses are _k
if (_misses == _k)
{ // recalculation.
OsmSharp.Logging.Log.TraceEvent("CHPreProcessor", TraceEventType.Information,
"Recalculating queue...");
CHPriorityQueue new_queue = new CHPriorityQueue();
HashSet <KeyValuePair <uint, float> > recalculated_weights =
new HashSet <KeyValuePair <uint, float> >();
int totalCadinality = 0;
foreach (uint vertex in _queue)
{
recalculated_weights.Add(
new KeyValuePair <uint, float>(vertex, _calculator.Calculate(vertex)));
var arcs = _target.GetEdges(vertex);
if (arcs != null)
{
totalCadinality = arcs.Length + totalCadinality;
}
}
foreach (KeyValuePair <uint, float> pair in recalculated_weights)
{
new_queue.Enqueue(pair.Key, pair.Value);
}
OsmSharp.Logging.Log.TraceEvent("CHPreProcessor", TraceEventType.Information,
"Average card: {0}", (double)totalCadinality / (double)recalculated_weights.Count);
_queue = new_queue;
_missesQueue.Clear();
_misses = 0;
}
else
{ // no recalculation.
if (priority > current_priority)
{ // re-enqueue the weight.
_queue.Enqueue(first_queued, priority);
}
else
{
//if (this.CanBeContracted(first_queued))
//{ // yet, this vertex can be contracted!
_queue.Remove(first_queued);
return(first_queued);
}
}
}
// check the queue.
if (_queue.Count > 0)
{
throw new Exception("Unqueued items left!, CanBeContracted is too restrictive!");
}
return(null); // all nodes have been contracted.
}