public void Norm2Test()
{
double[,] a =
{
{ 2, 1, 5 },
{ 2, 2, 2 },
{ 1, 6, 4 }
};
double expected = 9.071111071571606;
double actual = Norm.Norm2(a);
Assert.AreEqual(expected, actual, 1e-12);
}