static void Main(string[] args)
{
SquareMatrix2d wm = new SquareMatrix2d("g46.txt");
SquareMatrix2d minSpanTree = Algorithms.MakeMinSpannedTree(wm);
SquareMatrix2d K = Algorithms.MakeKirchhoffMatrix(wm);
double det = new SquareMatrix2d(K.Cofactor(0, 0)).Determinant();
Console.WriteLine("Source matrix\n");
Console.WriteLine(wm);
Console.WriteLine("Kirchhoff matrix\n");
Console.WriteLine(K.ToString());
Console.WriteLine("determinant of Kirchhoff matrix: {0}\n", det);
Console.WriteLine("Min spanned tree matrix\n");
Console.WriteLine(minSpanTree);
Console.ReadKey();
}
/// <summary>
/// Calculate a determinant of square matrix
/// http://en.wikipedia.org/wiki/Determinant
/// </summary>
/// <returns>det of matrix</returns>
public double Determinant()
{
double det = 1;
double EPS = 0.00000000001;
SquareMatrix2d m = new SquareMatrix2d(this);
int n = XSize;
for (int i = 0; i < n; i++)
{
int k = i;
for (int j = i + 1; j < n; ++j)
if (Math.Abs(m[j, i]) > Math.Abs(m[k, i])) k = j;
if (Math.Abs(m[k, i]) < EPS) return 0;
for (int it = 0; it < n; ++it)
{
double temp = m[i, it];
m[i, it] = m[k, it];
m[k, it] = temp;
}
if (i != k) det = -det;
det *= m[i, i];
for (int j = i + 1; j < n; ++j)
m[i, j] = m[i, j] / m[i, i];
for (int j = 0; j < n; ++j)
if (j != i && Math.Abs(m[j, i]) > EPS)
for (k = i + 1; k < n; ++k)
m[j, k] = m[j, k] - (m[i, k] * m[j, i]);
}
return det;
}
public SquareMatrix2d(SquareMatrix2d m)
: base(m)
{
}
private void UpdateGraphInfo()
{
SquareMatrix2d K = Algorithms.MakeKirchhoffMatrix(srcMatrixModel);
double det = new SquareMatrix2d(K.Cofactor(0, 0)).Determinant();
statusBar.Text = "this graph contains the " + det.ToString() + " spanned trees";
}
private void openToolStripMenuItem_Click(object sender, EventArgs e)
{
if (openMatrixFile.ShowDialog() == DialogResult.OK)
{
srcMatrixModel = new SquareMatrix2d(openMatrixFile.FileName);
srcMatrixView = InitSrcMatrixView(srcMatrixModel, srcMatrixView);
}
}
private void newToolStripMenuItem_Click(object sender, EventArgs e)
{
NewGraphCreateDialog creator = new NewGraphCreateDialog();
creator.Owner = this;
creator.ShowDialog();
if (IntData.Value >= 2)
{
srcMatrixModel = new SquareMatrix2d(IntData.Value, 0);
srcMatrixView = InitSrcMatrixView(srcMatrixModel, srcMatrixView);
}
this.Refresh();
}
private void makeMinSpannedTreeToolStripMenuItem_Click(object sender, EventArgs e)
{
minSpannedTreeModel = MakeMinSpannedTree(srcMatrixView);
spannedTreeView = InitSpannedTreeView(minSpannedTreeModel, spannedTreeView);
}
private SquareMatrix2d MakeMinSpannedTree(DataGridView matrixView)
{
matrixView = srcMatrixView;
SquareMatrix2d m = new SquareMatrix2d(matrixView.ColumnCount, 0.0);
SquareMatrix2d tree = new SquareMatrix2d(matrixView.ColumnCount, 0.0);
for (int i = 0; i < m.XSize; i++)
{
for (int j = 0; j < m.YSize; j++)
{
m[i, j] = Convert.ToDouble(matrixView.Rows[i].Cells[j].Value);
}
}
tree = Algorithms.MakeMinSpannedTree(m);
return tree;
}
