/// <summary>
/// Adds an incidence matrix for the STS(v) to the log file. Logfile has to be created beforehand.
/// Rows of the matrix represent vertices and the colums represent the triples.
/// If a triple contains an vertex, the value of the coresponding martix element is 1. Otherwise it's 0.
/// </summary>
/// <param name="sts"></param>
public static void AppendIncidenceMatrix(SteinerTripleSystem sts)
{
using (StreamWriter streamWriter = new StreamWriter(path, true))
{
List<string> matrixRows = new List<string>();
for (int i = 1; i <= sts.NumVertex(); i++)
{
matrixRows.Add(string.Empty);
}
foreach (Triple tr in sts)
{
for (int i = 1; i <= sts.NumVertex(); i++)
{
if (tr.X == i || tr.Y == i || tr.Z == i)
{
matrixRows[i - 1] += "1 ";
}
else
{
matrixRows[i - 1] += "0 ";
}
}
}
foreach (string line in matrixRows)
{
streamWriter.Write(line.Trim() + "\n");
}
streamWriter.Write("\n");
}
}
/// <summary>
/// Generates a different decomposition (possibly isomorphic)
/// </summary>
/// <returns>STS(v)</returns>
public SteinerTripleSystem NextDecomposition(SteinerTripleSystem sts)
{
RemoveRandBlocks(sts);
while (NumBlocks < v * (v - 1) / 6)
{
Switch();
}
return ConstructBlocks(v, Other);
}
/// <summary>
/// Creates a log file with a single incidence matrix
/// Log file starts with v and b
/// UNIX line endings
/// </summary>
/// <param name="logPath">Path of the log file</param>
public static void CreateLogFile(string logPath, SteinerTripleSystem sts)
{
path = logPath;
using (StreamWriter streamWriter = new StreamWriter(path, false))
{
//Write v and b to the first line of the logfile
streamWriter.Write(sts.NumVertex().ToString() +" " + sts.NumTriples().ToString() + "\n");
streamWriter.Write("\n");
}
AppendIncidenceMatrix(sts);
}
/// <summary>
/// Starts the Bose construction
/// </summary>
/// <param name="v">Number of vertices in a graph</param>
/// <returns>STS(v) generated by the construction</returns>
public SteinerTripleSystem StartAlgorithm(int v)
{
this.v = v;
this.n = (v - 3) / 6;
this.b = v * (v - 1) / 6;
this.quasigroup = new Quasigroup(2 * n + 1);
this.sts = new SteinerTripleSystem(v, b);
CreateTypeOne();
CreateTypeTwo();
return this.sts;
}
/// <summary>
/// Removes a random number of blocks from the decomposition.
/// </summary>
private void RemoveRandBlocks(SteinerTripleSystem sts)
{
Random rand = new Random();
for (int i = 0; i < sts.NumTriples(); i++)
{
bool removeBlock = rand.NextDouble() > ALPHA;
if (removeBlock)
{
Triple triple = sts.GetElement(i);
RemoveBlock(triple.X, triple.Y, triple.Z);
}
}
}
/// <summary>
/// Constructs the block set B that contains all the triples in the STS(v)
/// </summary>
/// <param name="v">Number of vertices</param>
/// <param name="Other">Array that keeps track of the third point in a block containing x and y</param>
/// <returns>STS(v) generated by the algorithm</returns>
protected SteinerTripleSystem ConstructBlocks(int v, int[,] Other)
{
SteinerTripleSystem sts = new SteinerTripleSystem(v, b);
int z;
for (int x = 1; x <= v; x++)
{
for (int y = x + 1; y <= v; y++)
{
z = Other[x, y];
if (z > y)
{
sts.AddTriple(x, y, z);
}
}
}
return sts;
}
/// <summary>
/// Starts the graph decompostition
/// </summary>
private void startDecompostion()
{
this.isDecompositionStarted = true;
this.sts = this.algorithm.StartAlgorithm(this.numVertex);
showDecompositionButtons();
hideAlgorithmPickerButtons();
}
/// <summary>
/// Removes old graph elements
/// </summary>
private void clearGraphElements()
{
this.canvasMain.Children.Clear();
this.vertexDictionary.Clear();
this.edgeDictionary.Clear();
this.sts = null;
this.index = 0;
this.isDecompositionStarted = false;
}