public void L2Test()
        {
            const double lambda = 1.0;
            var          reg    = new L2();
            var          mat    = new Matrix(10, 10);

            mat.InRandomize();

            Assert.IsTrue(Math.Abs(mat.FrobeniusNorm() * lambda - reg.CalculateNorm(mat)) < 0.1, reg.Type().ToString() + " Regularization.");
        }