public ClosestPointSearchResult FindClosestPoints(IPoint[] array)
{
Array.Sort(array, new PointComparerByFirstCoordinate());
var result = new ClosestPointSearchResult();
FindClosestPointsInternal(array, 0, array.Length, result);
return(result);
}
private void FindClosestPointsInternal(IPoint[] array, int begin, int end, ClosestPointSearchResult result)
{
if (end - begin < 2)
{
result.Distance = Double.MaxValue;
return;
}
var median = begin + (end - begin) / 2;
var result1 = new ClosestPointSearchResult();
var result2 = new ClosestPointSearchResult();
Parallel.Invoke(() => FindClosestPointsInternal(array, begin, median, result1),
() => FindClosestPointsInternal(array, median, end, result2));
BoundaryMerge(array, begin, end, result1, result2, result);
}
public ClosestPointSearchResult FindClosestPoints(IPoint[] points)
{
var result = new ClosestPointSearchResult {
Distance = Double.MaxValue
};
for (var i = 0; i < points.Length; i++)
{
for (var j = i + 1; j < points.Length; j++)
{
var distance = points[i].CalculateDistance(points[j]);
if (distance < result.Distance)
{
result.Distance = distance;
result.Point1 = points[i];
result.Point2 = points[j];
}
}
}
return(result);
}
private void BoundaryMerge(IPoint[] array, int begin, int end, ClosestPointSearchResult r1, ClosestPointSearchResult r2, ClosestPointSearchResult rOut)
{
// find minimal result
var minimal = r1.Distance > r2.Distance ? r2 : r1;
var minDistance = minimal.Distance;
rOut.Distance = minDistance;
rOut.Point1 = minimal.Point1;
rOut.Point2 = minimal.Point2;
// find possible smaller distance on boundary
var median = begin + (end - begin) / 2;
var b1 = median;
while (b1 > begin && array[b1].FirstCoordinate > array[median].FirstCoordinate - minDistance)
{
b1--;
}
var b2 = median;
while (b2 < end && array[b2].FirstCoordinate < array[median].FirstCoordinate + minDistance)
{
b2++;
}
for (var i = b1; i < b2; i++)
{
for (var j = i + 1; j < b2; j++)
{
var distance = array[i].CalculateDistance(array[j]);
if (distance < rOut.Distance)
{
rOut.Distance = distance;
rOut.Point1 = array[i];
rOut.Point2 = array[j];
}
}
}
}
