private static List <Neighbor> GetNeighborsByDistance(LeafNode leafNode, IDictionary <int, List <LeafNode> > buckets, IDistanceMetric distanceMetric)
{
var neighbors = distanceMetric.SignificantCoordinates(leafNode.Coords)
// Get every node with at least one shared match in common
.SelectMany(coord => buckets.TryGetValue(coord, out var bucket) ? bucket : Enumerable.Empty <LeafNode>())
// We only need one direction A -> B (not also B -> A) since we're ultimately going to look at the smallest distances.
.Where(neighborNode => neighborNode.Index < leafNode.Index)
// Make sure that each node is considered only once (might have been in more than one bucket if more than one shared match in common.
.Distinct()
.Select(neighborNode => new Neighbor(neighborNode, leafNode))
.LowestN(neighbor => neighbor.DistanceSquared, _maxNeighbors)
.ToList();
return(neighbors);
}
private static List <Neighbor> GetNeighborsByDistance(IEnumerable <LeafNode> leafNodesAll, LeafNode leafNode, IDistanceMetric distanceMetric)
{
var neighbors = leafNodesAll
.Where(neighborNode => neighborNode.Index < leafNode.Index)
.Select(neighborNode => new Neighbor(neighborNode, leafNode))
.Where(neighbor => neighbor.DistanceSquared != double.PositiveInfinity)
.LowestN(neighbor => neighbor.DistanceSquared, _maxNeighbors)
.ToList();
return(neighbors);
}
