Accord.Tests.Statistics.PrincipalComponentAnalysisTest.ExceptionTest C# (CSharp) Method

        public void ExceptionTest()
        {
            double[,] data = 
            {
                { 1, 2 },
                { 5, 2 },
                { 2, 2 },
                { 4, 2 },
            };


            var pca = new PrincipalComponentAnalysis(data, AnalysisMethod.Standardize);

            bool thrown = false;

            try { pca.Compute(); }
            catch (ArithmeticException ex)
            {
                ex.ToString();
                thrown = true;
            }

            // Default behavior changed: now an exception is not thrown anymore.
            // Instead, a small constant is added when computing standard deviations.
            Assert.IsFalse(thrown);

            var str1 = pca.SingularValues.ToCSharp();
            var str2 = pca.ComponentVectors.ToCSharp();

            Assert.IsTrue(pca.SingularValues.IsEqual(new double[] { 1.73205080756888, 0 }, 1e-7));
            Assert.IsTrue(pca.ComponentVectors.IsEqual(new double[][] {
                new double[] { 1, 0 },
                new double[] { 0, -1 }
            }, 1e-7));
        }