public void Matrix33Inverse()
{
var m = new Matrix3D(4, 6, 2, 4, 67, 8, 0, 1, 34);
Assert.AreNotEqual(0d, m.Determinant());
var m_1 = m.Inverse;
var ident = m_1 * m;
var det = ident.Determinant();
Assert.AreEqual(1d, det, 0.000001);
Assert.AreEqual(3d, ident.M11 + ident.M22 + ident.M33, 0.000001);
}
void Matrix3DTest()
{
var m = new Matrix3D(new double[] {
1, .5, 6,
.1, 2, .05,
.7, 11, .55
});
// det
Assert.True(m.Determinant().EqualsTol(1e-6, -1.260));
// inv
Assert.True(m.Inverse().EqualsTol(1e-3, new Matrix3D(new double[] {
-0.437, -52.163, 9.504,
0.016, 2.897, -0.437,
0.238, 8.452, -1.548
})));
// solve
Assert.True(m.Solve(1.1, 2.2, 3.3).EqualsTol(1e-3, new Vector3D(-83.875, 4.95, 13.75)));
}
public void Determinant()
{
Matrix3D m = new Matrix3D(0, 0, 1,
0, 1, 0,
1, 0, 0);
Assert.AreEqual(-1, m.Determinant());
m = new Matrix3D(
5, 7, 1,
17, 2, 64,
10, 14, 2);
Assert.AreEqual(0, m.Determinant());
m = new Matrix3D(
1, 2, 3,
4, 5, 6,
7, 8, 9);
Assert.AreEqual(0, m.Determinant());
}