// numerics
public MatrixNd IdentityMatrix(int r, int c)
{
MatrixNd mat = new MatrixNd(r, c);
for (int i = 0; i < r; ++i)
{
mat[i, i] = 1.0;
}
return(mat);
}
static public MatrixNd operator *(double factor, MatrixNd m)
{
MatrixNd mat = new MatrixNd(m);
for (int i = 0; i < m.length; ++i)
{
mat[i] *= factor;
}
return(mat);
}
public MatrixNd(MatrixNd mat)
{
M = mat.Row;
N = mat.Col;
length = M * N;
arr = new double[length];
for (int i = 0; i < length; ++i)
{
arr[i] = mat.arr[i];
}
}
public MatrixNd Transpose()
{
MatrixNd mat = new MatrixNd(N, M);
for (int i = 0; i < M; ++i)
{
for (int j = 0; j < N; ++j)
{
mat[j, i] = this[i, j];
}
}
return(mat);
}
static public MatrixNd operator /(double factor, MatrixNd m)
{
MatrixNd mat = new MatrixNd(m);
if (factor == 0)
{
throw new DivideByZeroException();
}
for (int i = 0; i < m.length; ++i)
{
mat[i] /= factor;
}
return(mat);
}
static public MatrixNd operator -(MatrixNd m1, MatrixNd m2)
{
if (m1.M != m2.M || m1.N != m2.N)
{
return(null);
}
MatrixNd m = new MatrixNd(m1);
for (int i = 0; i < m1.length; ++i)
{
m[i] -= m2[i];
}
return(m);
}
static public MatrixNd operator *(MatrixNd m1, MatrixNd m2)
{
if (m1.Col != m2.Row)
{
return(null);
}
MatrixNd mat = new MatrixNd(m1.Row, m2.Col);
for (int i = 0; i < m1.Row; ++i)
{
for (int j = 0; j < m2.Col; ++j)
{
for (int k = 0; k < m1.Col; ++k)
{
mat[i, j] += m1[i, k] * m2[k, j];
}
}
}
return(mat);
}
