public void InverseWithNearSingularMatrix()
{
Matrix22D m = new Matrix22D(0.0001, 0,
0, 0.0001);
Vector2D v = Vector2D.One;
Vector2D w = m * v;
Assert.IsTrue(Vector2D.AreNumericallyEqual(v, m.Inverse * w));
Assert.IsTrue(Matrix22D.AreNumericallyEqual(Matrix22D.Identity, m * m.Inverse));
}
public void Inverse()
{
Assert.AreEqual(Matrix22D.Identity, Matrix22D.Identity.Inverse);
Matrix22D m = new Matrix22D(1, 2, 3, 4);
Vector2D v = Vector2D.One;
Vector2D w = m * v;
Assert.IsTrue(Vector2D.AreNumericallyEqual(v, m.Inverse * w));
Assert.IsTrue(Matrix22D.AreNumericallyEqual(Matrix22D.Identity, m * m.Inverse));
}
public void AreEqualWithEpsilon()
{
double epsilon = 0.001;
Matrix22D m0 = new Matrix22D(columnMajor, MatrixOrder.ColumnMajor);
Matrix22D m1 = new Matrix22D(columnMajor, MatrixOrder.ColumnMajor);
m1 += new Matrix22D(0.002);
Matrix22D m2 = new Matrix22D(columnMajor, MatrixOrder.ColumnMajor);
m2 += new Matrix22D(0.0001);
Assert.IsTrue(Matrix22D.AreNumericallyEqual(m0, m0, epsilon));
Assert.IsFalse(Matrix22D.AreNumericallyEqual(m0, m1, epsilon));
Assert.IsTrue(Matrix22D.AreNumericallyEqual(m0, m2, epsilon));
}
public void AreEqual()
{
double originalEpsilon = Numeric.EpsilonD;
Numeric.EpsilonD = 1e-8;
Matrix22D m0 = new Matrix22D(columnMajor, MatrixOrder.ColumnMajor);
Matrix22D m1 = new Matrix22D(columnMajor, MatrixOrder.ColumnMajor);
m1 += new Matrix22D(0.000001);
Matrix22D m2 = new Matrix22D(columnMajor, MatrixOrder.ColumnMajor);
m2 += new Matrix22D(0.00000001);
Assert.IsTrue(Matrix22D.AreNumericallyEqual(m0, m0));
Assert.IsFalse(Matrix22D.AreNumericallyEqual(m0, m1));
Assert.IsTrue(Matrix22D.AreNumericallyEqual(m0, m2));
Numeric.EpsilonD = originalEpsilon;
}
public void MultiplyMatrix()
{
Matrix22D m = new Matrix22D(12, 23, 45, 67);
Assert.AreEqual(Matrix22D.Zero, Matrix22D.Multiply(m, Matrix22D.Zero));
Assert.AreEqual(Matrix22D.Zero, Matrix22D.Multiply(Matrix22D.Zero, m));
Assert.AreEqual(m, Matrix22D.Multiply(m, Matrix22D.Identity));
Assert.AreEqual(m, Matrix22D.Multiply(Matrix22D.Identity, m));
Assert.IsTrue(Matrix22D.AreNumericallyEqual(Matrix22D.Identity, Matrix22D.Multiply(m, m.Inverse)));
Assert.IsTrue(Matrix22D.AreNumericallyEqual(Matrix22D.Identity, Matrix22D.Multiply(m.Inverse, m)));
Matrix22D m1 = new Matrix22D(columnMajor, MatrixOrder.ColumnMajor);
Matrix22D m2 = new Matrix22D(12, 23, 45, 67);
Matrix22D result = Matrix22D.Multiply(m1, m2);
for (int column = 0; column < 2; column++)
{
for (int row = 0; row < 2; row++)
{
Assert.AreEqual(Vector2D.Dot(m1.GetRow(row), m2.GetColumn(column)), result[row, column]);
}
}
}
