public int CompareTo(BeamNode <T> other)
{
// This method is important for comparing and ranking nodes in terms of their relative weights.
var result = this.Weight.CompareTo(other.Weight);
return(result);
}
// Construction
internal BeamNode(BeamSearch <T> beam, double weight)
{
PreviousNode = null;
Weight = weight;
Item = default(T);
_beam = beam;
Depth = 0;
}
// Construction
/// <summary>Creates a new <c>BeanSearch</c> structure.</summary>
/// <param name="rootWeight">
/// If you are using logarithmic numbers, set the value to 0. If you are using percentages, set this value to 1.
/// </param>
public BeamSearch(double rootWeight)
{
_root = new BeamNode <T>(this, rootWeight);
Level.Add(new List <BeamNode <T> >()
{
_root
});
}
// Methods
/// <summary>Adds the specified <c>item</c> as the next node in the <c>BeamSearch</c> structure.</summary>
/// <param name="weight">
/// This is the weight of this node, which will determine which nodes are given priority by the <c>BeamSearch</c> structure.
/// </param>
public void AddNextNode(T item, double weight)
{
var newNode = new BeamNode <T>(this, item, weight);
if (newNode.Depth >= _beam.Level.Count)
{
Debug.Assert(_beam.Level.Count == newNode.Depth);
_beam.Level.Add(new List <BeamNode <T> >());
}
_beam.Level[newNode.Depth].Add(newNode);
}
/// <summary><para>Creates a new BeamNode instance.
/// </para><para>Next, call parentNode.AddChild(...) to add this node to the appropriate level of the Beam.
/// </para></summary>
/// <param name="parent"></param>
/// <param name="item"></param>
/// <param name="weight"></param>
public BeamNode(BeamNode <T> parent, T item, double weight)
{
Debug.Assert(parent != null);
Debug.Assert(item != null);
PreviousNode = parent;
Item = item;
Weight = weight;
_beam = parent._beam;
Depth = parent.Depth + 1;
}
// Methods
/// <summary>Returns the best sequence of items stored in the Beam.</summary>
public T[] GetBestSequence()
{
T[] results = new T[Level.Count - 1];
var bestSequence = SearchHelper.GetMaxNItems(1, Level[Level.Count - 1]);
BeamNode <T> currentLevel = Level[Level.Count - 1][bestSequence[0]];
while (currentLevel.Depth > 0)
{
results[currentLevel.Depth - 1] = currentLevel.Item;
currentLevel = currentLevel.PreviousNode;
}
return(results);
}
