public void Determinant2x2()
{
var b = new RTF.Matrix(2, 2);
b.SetRow(0, new double[] { 1, 5 });
b.SetRow(1, new double[] { -3, 2 });
Assert.Equal(17, b.Determinant());
}
public void Determinant4x4()
{
var e = new RTF.Matrix(4, 4);
e.SetRow(0, new double[] { -2, -8, 3, 5 });
e.SetRow(1, new double[] { -3, 1, 7, 3 });
e.SetRow(2, new double[] { 1, 2, -9, 6 });
e.SetRow(3, new double[] { -6, 7, 7, -9 });
Assert.Equal(690, RTF.Matrix.Cofactor(e, 0, 0));
Assert.Equal(447, RTF.Matrix.Cofactor(e, 0, 1));
Assert.Equal(210, RTF.Matrix.Cofactor(e, 0, 2));
Assert.Equal(51, RTF.Matrix.Cofactor(e, 0, 3));
Assert.Equal(-4071, e.Determinant());
}
public void Inverse()
{
var e = new RTF.Matrix(4, 4);
e.SetRow(0, new double[] { -5, 2, 6, -8 });
e.SetRow(1, new double[] { 1, -5, 1, 8 });
e.SetRow(2, new double[] { 7, 7, -6, -7 });
e.SetRow(3, new double[] { 1, -3, 7, 4 });
double r1 = -160d / 532;
double r2 = 105d / 532;
var b = e.Inverse();
Assert.Equal(532, e.Determinant());
Assert.Equal(-160, RTF.Matrix.Cofactor(e, 2, 3));
Assert.Equal(r1, b[3, 2]);
Assert.Equal(105, RTF.Matrix.Cofactor(e, 3, 2));
Assert.Equal(r2, b[2, 3]);
}