private static double[][] CholeskyDecompositionParallel(double[][] matrix)
{
double[][] lower = MatrixHelper.MatrixCreate(matrix.Length, matrix.Length);
// Decomposing a matrix
// into Lower Triangular
for (int i = 0; i < matrix.Length; i++)
{
for (int j = 0; j <= i; j++)
{
// Evaluating L(i, j)
// using L(j, j)
double sum = 0;
Parallel.For(0, j, k =>
{
sum += (lower[i][k] * lower[j][k]);
});
// summation for diagnols
if (j == i)
{
lower[j][j] = Math.Sqrt(matrix[j][j] - sum);
}
else
{
lower[i][j] = (matrix[i][j] - sum) / lower[j][j];
}
}
}
return(lower);
}
private static double[][] ConvertToBlockDiagonal(double[][] matrix, double k)
{
double[][] result = MatrixHelper.MatrixCreate(matrix.Length, matrix[0].Length);
for (int i = 0; i < matrix.Length; i++)
{
int finish = i / BlockSize * BlockSize + BlockSize;
for (int j = i / BlockSize * BlockSize; j < finish; j++)
{
result[i][j] = matrix[i][j];
}
}
return(result);
}
private static double[][] Transpose(double[][] decomposed)
{
double[][] lower = MatrixHelper.MatrixCreate(decomposed.Length, decomposed.Length);
for (int i = 0; i < decomposed.Length; i++)
{
for (int j = 0; j < decomposed.Length; j++)
{
lower[j][i] = decomposed[i][j];
}
}
return(lower);
}
private static double[][] GetGreenValuesMatrix(Bitmap bmp, int n)
{
double[][] result = MatrixHelper.MatrixCreate(n, n);
for (int x = 0; x < n; x++)
{
result[x] = new double[n];
for (int y = 0; y < n; y++)
{
result[x][y] = bmp.GetPixel(x, y).G;
}
}
return(result);
}