internal Core(Func <TItem, TItem, TDistance> distance, SmallWorld <TItem, TDistance> .Parameters parameters)
{
Distance = distance;
Parameters = parameters;
var initialSize = Math.Max(1024, parameters.InitialItemsSize);
Nodes = new List <Node>(initialSize);
Items = new List <TItem>(initialSize);
switch (Parameters.NeighbourHeuristic)
{
case NeighbourSelectionHeuristic.SelectSimple:
{
Algorithm = new Algorithms.Algorithm3 <TItem, TDistance>(this);
break;
}
case NeighbourSelectionHeuristic.SelectHeuristic:
{
Algorithm = new Algorithms.Algorithm4 <TItem, TDistance>(this);
break;
}
}
if (Parameters.EnableDistanceCacheForConstruction)
{
DistanceCache = new DistanceCache <TDistance>();
DistanceCache.Resize(parameters.InitialDistanceCacheSize, false);
}
DistanceCalculationsCount = 0;
}
internal IReadOnlyList <int> AddItems(IReadOnlyList <TItem> items, IProvideRandomValues generator, CancellationToken cancellationToken)
{
int newCount = items.Count;
var newIDs = new List <int>();
Items.AddRange(items);
DistanceCache?.Resize(newCount, false);
int id0 = Nodes.Count;
for (int id = 0; id < newCount; ++id)
{
Nodes.Add(Algorithm.NewNode(id0 + id, RandomLayer(generator, Parameters.LevelLambda)));
newIDs.Add(id0 + id);
cancellationToken.ThrowIfCancellationRequested();
}
return(newIDs);
}