public void GetDistanceBetweenFeatures_Works_As_Expected()
{
var feat1 = new Feature("place1", 0, 0);
var feat2 = new Feature("place2", 0, 5);
var distance = FeatureHelper.GetDistance(feat2, feat1);
Assert.Equal(5, distance);
}
public double FindDistanceToNearestNeighbour(KDNode currentNode, Feature goalFeature, KDNode closestNeighbour, double closestNeighbourDistance)
{
if (currentNode == null)
{
return(closestNeighbourDistance);
}
var currentDistance = FeatureHelper.GetDistance(currentNode.Feature, goalFeature);
if (currentDistance < closestNeighbourDistance)
{
if (currentNode.Feature != goalFeature)
{
closestNeighbour = currentNode;
closestNeighbourDistance = currentDistance;
}
}
if (currentNode.UseXAxis)
{
if (goalFeature.X < currentNode.Feature.X) //is goal.x LEFT current node.x? IF so, traverse LEFT, otherwise go RIGHT (easy to understand because this is X comparison node)
{
closestNeighbourDistance = FindDistanceToNearestNeighbour(currentNode.LeftNode, goalFeature, closestNeighbour, closestNeighbourDistance);
if (Math.Abs(currentNode.Feature.X - goalFeature.X) < closestNeighbourDistance)
{
closestNeighbourDistance = FindDistanceToNearestNeighbour(currentNode.RightNode, goalFeature, closestNeighbour, closestNeighbourDistance);
}
}
else
{
closestNeighbourDistance = FindDistanceToNearestNeighbour(currentNode.RightNode, goalFeature, closestNeighbour, closestNeighbourDistance);
if (Math.Abs(goalFeature.X - currentNode.Feature.X) < closestNeighbourDistance)
{
closestNeighbourDistance = FindDistanceToNearestNeighbour(currentNode.LeftNode, goalFeature, closestNeighbour, closestNeighbourDistance);
}
}
}
else
{
if (goalFeature.Y > currentNode.Feature.Y) //is goal.y ABOVE current node.y? IF so, traverse to RIGHT to go ABOVE (because this is a Y comparison node) otherwise go left to look down
{
closestNeighbourDistance = FindDistanceToNearestNeighbour(currentNode.RightNode, goalFeature, closestNeighbour, closestNeighbourDistance);
if (Math.Abs(currentNode.Feature.Y - goalFeature.Y) < closestNeighbourDistance)
{
closestNeighbourDistance = FindDistanceToNearestNeighbour(currentNode.LeftNode, goalFeature, closestNeighbour, closestNeighbourDistance);
}
}
else
{
closestNeighbourDistance = FindDistanceToNearestNeighbour(currentNode.LeftNode, goalFeature, closestNeighbour, closestNeighbourDistance);
if (Math.Abs(goalFeature.Y - currentNode.Feature.Y) < closestNeighbourDistance)
{
closestNeighbourDistance = FindDistanceToNearestNeighbour(currentNode.RightNode, goalFeature, closestNeighbour, closestNeighbourDistance);
}
}
}
return(closestNeighbourDistance);
}
