public static MatrixD operator *(MatrixD a, MatrixD b)
{
if (a.Columns != b.Rows) throw new ArgumentException("Unable to multiply matrices of different inner dimensions");
MatrixD x = new MatrixD(a.Rows, b.Columns);
int inner = a.Columns;
for (int r = 0, rows = x.Rows; r < rows; r++)
{
for (int c = 0, cols = x.Columns; c < cols; c++)
{
double d = 0.0;
for (int i = 0; i < inner; i++) d += a[r, i] * b[i, c];
x[r, c] = d;
}
}
return x;
}
public static MatrixD One(int rows, int columns)
{
MatrixD m = new MatrixD(rows, columns);
for (int r = 0; r < rows; r++)
{
for (int c = 0; c < columns; c++)
{
m[r, c] = 1.0;
}
}
return m;
}
public static MatrixD Identity(int dimensions)
{
MatrixD m = new MatrixD(dimensions, dimensions);
for (int r = 0, rows = dimensions; r < rows; r++)
{
for (int c = 0, cols = dimensions; c < cols; c++)
{
m[r, c] = (r == c) ? 1.0 : 0.0;
}
}
return m;
}
public MatrixD Transpose()
{
MatrixD t = new MatrixD(Columns, Rows);
for (int r = 0, rows = Rows; r < rows; r++)
{
for (int c = 0, cols = Columns; c < cols; c++)
{
t[c, r] = _matrix[r, c];
}
}
return t;
}