public void Inverse_Throws_IfDeterminantZero()
{
var values = new BigRational[2, 2]
{
{ 2, 8 },
{ 1, 4 }
};
var matrix = new ImmutableMatrix2x2(values);
Assert.Throws <InvalidOperationException>(() => matrix.Inverse());
}
public void Inverse_InvertsMatrix()
{
var values = new BigRational[2, 2]
{
{ 2, 5 },
{ 1, 4 }
};
var matrix = new ImmutableMatrix2x2(values);
var inverse = matrix.Inverse();
Assert.Equal(new BigRational(4, 3), inverse.UnderlyingValues[0, 0]);
Assert.Equal(new BigRational(-5, 3), inverse.UnderlyingValues[0, 1]);
Assert.Equal(new BigRational(-1, 3), inverse.UnderlyingValues[1, 0]);
Assert.Equal(new BigRational(2, 3), inverse.UnderlyingValues[1, 1]);
Assert.Equal(Constants.Matrices.I, matrix * inverse);
}