Improving the predictor: Hierarchical N-Gram

The N-Gram predictor can be improved by having a handler with several other predictors ranging from 1 to n, and obtaining the best possible action after comparing the best guess from each one of them.

Getting ready…

We need to make some adjustments prior to implementing the hierarchical N-Gram predictor.

Add the following member function to the NGramPredictor class:

public int GetActionsNum(ref T[] actions)
{
    string key = ArrToStrKey(ref actions);
    if (!data.ContainsKey(key))
        return 0;
    return data[key].total;
}

How to do it…

Just like the N-Gram predictor, building the hierarchical version takes a few steps:

1. Create the new class:

   using System;
   using System.Collections;
   using System.Text;
   
   public class HierarchicalNGramP<T>
   {
       
       public int threshold;
       public NGramPredictor<T>[] predictors;
       private int nValue;
   }

2. Implement the constructor for initializing member values:

   public HierarchicalNGramP(int windowSize)
   ...