/// <summary>
/// Method to determine the MCD value between two tickets
/// MCD(A,B) = max(|c(AB)-c(AA)|, |c(AB)-c(BB)|)/max(c(AA),c(BB))
/// </summary>
/// <param name="entity1">ICompressible ticket to operate MCD on</param>
/// <param name="entity2">ICompressible ticket to operate MCD on</param>
/// <returns>Double value representing the MCD value between the two tickets</returns>
private double getMCD(ICompressible entity1, ICompressible entity2)
{
double MCD_numerator;
double MCD_result;
// Create two StringCompressible objects of the entities concatenated to themselves
ICompressible AA = new StringCompressible (Encoding.ASCII.GetString(entity1.ToByteArray().Concat(entity1.ToByteArray()).ToArray()));
ICompressible BB = new StringCompressible (Encoding.ASCII.GetString(entity2.ToByteArray().Concat(entity2.ToByteArray()).ToArray()));
// Find c(AA) and c(BB)
double MCD_AA = (double) GetComplexity(AA);
double MCD_BB = (double) GetComplexity(BB);
// Find c(AB)
byte[] combinedArray = entity1.ToByteArray().Concat(entity2.ToByteArray()).ToArray();
double MCD_AB = (double)compressionSize(combinedArray);
// Find max( |c(AB)-c(AA)|, |c(AB)-c(BB)|)
if (Math.Abs(MCD_AB - MCD_AA) >= Math.Abs(MCD_AB - MCD_BB))
{
MCD_numerator = Math.Abs(MCD_AB - MCD_AA);
}
else
{
MCD_numerator = Math.Abs(MCD_AB - MCD_BB);
}
// Find MCD(A,B)
if (MCD_AA >= MCD_BB)
{
MCD_result = (MCD_numerator / MCD_AA);
}
else
{
MCD_result = (MCD_numerator / MCD_BB);
}
return MCD_result;
}
/// <summary>
/// Method to determine the NCD value between two tickets (ICompressible objects)
/// NCD(x,y) = {Z(xy) - min[Z(x), Z(y)]} / max[Z(x), Z(y)]
/// </summary>
/// <param name="entity1">ICompressible ticket to operate NCD on</param>
/// <param name="entity2">ICompressible ticket to operate NCD on</param>
/// <returns>Double value representing the NCD value between the two tickets</returns>
private double getNCD(ICompressible entity1, ICompressible entity2)
{
// Compress the tickets
int compressedEntity1 = GetComplexity(entity1);
int compressedEntity2 = GetComplexity(entity2);
// Concatenate the tickets
byte[] combinedArray = entity1.ToByteArray().Concat(entity2.ToByteArray()).ToArray();
// NCD_A = compressed size of the two tickets concatenated
double NCD_A = (double) compressionSize(combinedArray);
// NCD_B = min(compressed size of ticket 1, compressed size of ticket 2)
// NCD_C = max(compressed size of ticket 1, compressed size of ticket 2)
double NCD_B, NCD_C;
// Determine the values of NCD_B and NCD_C
if (compressedEntity1 >= compressedEntity2)
{
NCD_B = (double) compressedEntity2;
NCD_C = (double) compressedEntity1;
}
else
{
NCD_B = (double) compressedEntity1;
NCD_C = (double) compressedEntity2;
}
// Compute and return the NCD value
double NCD_result = (NCD_A - NCD_B) / NCD_C;
return NCD_result;
}
// Returns the size of the compressed ticket
public int GetComplexity(ICompressible entity)
{
// Return the complexity of the ticket if its been set (i.e. not zero)
if (entity.Complexity != 0)
{
return entity.Complexity;
}
// Set the complexity of the ticket for later use
entity.Complexity = compressionSize(entity.ToByteArray());
return entity.Complexity;
}