public Vector2 Mult(Matrix2 matrix)
{
return new Vector2(
tuple[0] * matrix.entry[0] + tuple[1] * matrix.entry[2],
tuple[0] * matrix.entry[1] + tuple[1] * matrix.entry[3]);
}
public Matrix2 Transpose()
{
Matrix2 result = new Matrix2();
for (int i = 0; i < 4; i++)
for (int j = 0; j < 4; j++)
result.entry[I(i, j)] = entry[I(j, i)];
return result;
}
public Matrix2 TransposeTimes(Matrix2 matrix)
{
// P = A^T*B, P[r][c] = sum_m A[m][r]*B[m][c]
Matrix2 result = new Matrix2();
for (int row = 0; row < 2; row++)
{
for (int col = 0; col < 2; col++)
{
int i = I(row, col);
result.entry[i] = 0;
for (int mid = 0; mid < 2; mid++)
result.entry[i] += entry[I(mid, row)] * matrix.entry[I(mid, col)];
}
}
return result;
}
public Matrix2 Sub(Matrix2 matrix)
{
Matrix2 result = new Matrix2();
for (int i = 0; i < 4; i++)
result.entry[i] = entry[i] - matrix.entry[i];
return result;
}
public Matrix2 TimesTranspose(Matrix2 matrix)
{
// P = A*B^T, P[r][c] = sum_m A[r][m]*B[c][m]
Matrix2 result = new Matrix2();
for (int row = 0; row < 2; row++)
{
for (int col = 0; col < 2; col++)
{
int i = I(row, col);
result.entry[i] = 0;
for (int mid = 0; mid < 2; mid++)
result.entry[i] += entry[I(row, mid)] * matrix.entry[I(col, mid)];
}
}
return result;
}
public Matrix2 Negative()
{
Matrix2 result = new Matrix2();
for (int i = 0; i < 4; i++)
result.entry[i] = -entry[i];
return result;
}
public Matrix2 Mult(double scalar)
{
Matrix2 result = new Matrix2();
for (int i = 0; i < 4; i++)
result.entry[i] = entry[i] * scalar;
return result;
}
public Matrix2 Mult(Matrix2 matrix)
{
Matrix2 result = new Matrix2();
for (int row = 0; row < 2; row++)
{
for (int col = 0; col < 2; col++)
{
int i = I(row, col);
result.entry[i] = 0;
for (int mid = 0; mid < 2; mid++)
result.entry[i] += entry[I(row, mid)] * matrix.entry[I(mid, col)];
}
}
return result;
}
public Matrix2 Inverse()
{
double det = Determinant();
if (System.Math.Abs(det) > 0)
{
Matrix2 result = new Matrix2();
double invDet = 1 / det;
result.entry[I(0, 0)] = entry[3] * invDet;
result.entry[I(0, 1)] = -entry[1] * invDet;
result.entry[I(1, 0)] = -entry[2] * invDet;
result.entry[I(1, 1)] = entry[0] * invDet;
return result;
}
else
return Matrix2.Zero;
}
public Matrix2 Div(double scalar)
{
Matrix2 result = new Matrix2();
if (scalar != 0.0)
{
double invScalar = 1 / scalar;
for (int i = 0; i < 4; i++)
result.entry[i] = invScalar * entry[i];
}
else
for (int i = 0; i < 4; i++)
result.entry[i] = double.MaxValue;
return result;
}
