// ******************************************************************
/// <summary>
///
/// </summary>
/// <param name="threadUsage">Using ConvexHullThreadUsage.All will only use all thread for the first pass (se quadrant limits) then use only 4 threads for pass 2 (which is the actual limit).</param>
public void CalcConvexHull(ConvexHullThreadUsage threadUsage = ConvexHullThreadUsage.OneOrFour)
{
if (IsZeroData())
{
return;
}
if (threadUsage == ConvexHullThreadUsage.AutoSelect || threadUsage == ConvexHullThreadUsage.OneOrFour)
{
if (Environment.ProcessorCount == 1)
{
threadUsage = ConvexHullThreadUsage.OnlyOne;
}
// It's around 10 000 000 points on a 12 cores that some advantages really start to appear
else if (threadUsage == ConvexHullThreadUsage.OneOrFour || Environment.ProcessorCount <= 4 || _listOfPoint.Count < 10000000)
{
threadUsage = ConvexHullThreadUsage.FixedFour;
}
else
{
threadUsage = ConvexHullThreadUsage.All;
}
}
// There is no need to start more than 1 thread. It will not be usefull on a single core machine.
if (threadUsage == ConvexHullThreadUsage.OnlyOne)
{
SetQuadrantLimitsOneThread();
_q1.PrepareQuadrant(true);
_q2.PrepareQuadrant(true);
_q3.PrepareQuadrant(true);
_q4.PrepareQuadrant(true);
}
else
{
bool isSkipSetQuadrantLimit = false;
if (threadUsage == ConvexHullThreadUsage.All)
{
isSkipSetQuadrantLimit = true;
SetQuadrantLimitsUsingAllThreads();
}
Quadrant[] quadrants = new Quadrant[4];
quadrants[0] = _q1;
quadrants[1] = _q2;
quadrants[2] = _q3;
quadrants[3] = _q4;
Task[] tasks = new Task[4];
for (int n = 0; n < tasks.Length; n++)
{
int nLocal = n; // Prevent Lambda internal closure error.
tasks[n] = Task.Factory.StartNew(() => quadrants[nLocal].PrepareQuadrant(isSkipSetQuadrantLimit));
}
Task.WaitAll(tasks);
}
}
// ******************************************************************
private void Init(IReadOnlyList <Point> listOfPoint, bool shouldCloseTheGraph, int initialResultGuessSize)
{
_listOfPoint = listOfPoint;
_shouldCloseTheGraph = shouldCloseTheGraph;
if (initialResultGuessSize <= 0 && !IsZeroData())
{
initialResultGuessSize = Math.Min((int)Math.Sqrt(listOfPoint.Count), 100);
}
_q1 = new QuadrantSpecific1(_listOfPoint, initialResultGuessSize);
_q2 = new QuadrantSpecific2(_listOfPoint, initialResultGuessSize);
_q3 = new QuadrantSpecific3(_listOfPoint, initialResultGuessSize);
_q4 = new QuadrantSpecific4(_listOfPoint, initialResultGuessSize);
}