Accord.Tests.Math.MatrixTest.ProductsTest1 C# (CSharp) Method

        public void ProductsTest1()
        {
            double[] u = { 1, 6, 3 };
            double[] v = { 9, 4, 2 };

            // products
            double inner = u.InnerProduct(v);    // 39.0
            double[,] outer = u.OuterProduct(v); // see below
            double[] kronecker = u.KroneckerProduct(v); // { 9, 4, 2, 54, 24, 12, 27, 12, 6 }
            double[][] cartesian = u.CartesianProduct(v); // all possible pair-wise combinations

            Assert.AreEqual(39, inner);
            Assert.IsTrue(new double[,] 
            { 
               {  9,  4,  2 },
               { 54, 24, 12 },
               { 27, 12,  6 },
            }.IsEqual(outer));

            Assert.IsTrue(new double[] { 9, 4, 2, 54, 24, 12, 27, 12, 6 }
                .IsEqual(kronecker));


            // addition
            double[] addv = u.Add(v); // { 10, 10, 5 }
            double[] add5 = u.Add(5); // {  6, 11, 8 }

            Assert.IsTrue(addv.IsEqual(10, 10, 5));
            Assert.IsTrue(add5.IsEqual(6, 11, 8));

            double[] abs = u.Abs();   // { 1, 6, 3 }
            double[] log = u.Log();   // { 0, 1.79, 1.09 }
            double[] cos = u.Apply(Math.Cos); // { 0.54, 0.96, -0.989 }

            Assert.IsTrue(abs.IsEqual(new double[] { 1, 6, 3 }));
            Assert.IsTrue(log.IsEqual(new double[] { 0, 1.79, 1.09 }, 1e-2));
            Assert.IsTrue(cos.IsEqual(new double[] { 0.54, 0.96, -0.989 }, 1e-2));

            double[,] m = 
            {
                { 0, 5, 2 },
                { 2, 1, 5 }
            };

            double[] vcut = v.Submatrix(0, 1); // { 9, 4 }
            Assert.IsTrue(new double[] { 9, 4 }.IsEqual(vcut));

            double[] mv = m.Multiply(v); // { 24, 32 }
            double[] vm = vcut.Multiply(m); // { 8, 49, 38 }
            double[,] md = m.MultiplyByDiagonal(v); // { { 0, 20, 4 }, { 18, 4, 10 } }
            double[,] mmt = m.MultiplyByTranspose(m); // { { 29, 15 }, { 15, 30 } }

            Assert.IsTrue(new double[] { 24, 32 }.IsEqual(mv));
            Assert.IsTrue(new double[] { 8, 49, 38 }.IsEqual(vm));
            Assert.IsTrue(new double[,] { { 0, 20, 4 }, { 18, 4, 10 } }.IsEqual(md));
            Assert.IsTrue(new double[,] { { 29, 15 }, { 15, 30 } }.IsEqual(mmt));
        }