public static Codeword[] PrepareSFCode(double[] Probabilities)
{
double[] Probs = (double[])Probabilities.Clone();
int[] Values = new int[Probs.Length];
for (int i = 0; i < Values.Length; i++)
{
Values[i] = i;
}
Array.Sort(Probs, Values);
int[] Lengths = Probs.Select((x) => (int)Ceiling(-Log(x) / Log(2))).ToArray();
BigInteger counter = new BigInteger(0);
int Clength = Lengths[Lengths.Length - 1];
Codeword[] CSet = new Codeword[Probabilities.Length];
for (int i = Lengths.Length - 1; i >= 0; i--)
{
if (Lengths[i] > Clength)
{
counter >>= (Clength - Lengths[i]); Clength = Lengths[i];
}
CSet[Values[i]] = new Codeword()
{
Length = Clength, CodeWord = GetBits(counter, Clength)
};
CSet[Values[i]].CodeWord.Length = Clength;
counter++;
}
return(CSet);
}
public static Codeword[] PrepareHuffmanCode(double[] Probabilities)
{
List <HNode> Roots = new List <HNode>();
for (int i = 0; i < Probabilities.Length; i++)
{
HNode hn = new HNode()
{
Probability = Probabilities[i], LeafNumber = i
};
Roots.Add(hn);
}
double SmallestProb = Roots[0].Probability;
while (Roots.Count != 1)
{
HNode a = Roots[0];
HNode b = Roots[1];
Roots.RemoveRange(0, 2);
HNode Ha = new HNode()
{
Probability = a.Probability + b.Probability, LeafNumber = -1, Zero = a, One = b
};
Roots.Add(Ha);
Roots.Sort(Ha);
}
HNode Rootnode = Roots[0];
System.Diagnostics.Debug.Assert(Math.Abs(Rootnode.Probability - 1.0) < SmallestProb / 10);
Codeword[] Result = new Codeword[Probabilities.Length];
BitArray BA = new BitArray(Probabilities.Length);
GenerateCodewordList(Rootnode, BA, Result, 0);
return(Result);
}
