public void tf_mean_test()
        {
            using (var K = new TensorFlowBackend())
            {
                var x = K.variable(array: new double[, ] {
                    { 1, 2, 3 }, { 4, 5, 6 }
                }, dtype: DataType.Double);
                {
                    double a = (double)K.mean(x, axis: new[] { 0, 1 }).eval();
                    Assert.AreEqual(3.5, a);

                    double[] b = (double[])K.mean(x, axis: new[] { 0 }).eval();
                    Assert.AreEqual(new[] { 2.5, 3.5, 4.5 }, b);

                    double[] c = (double[])K.mean(x, axis: new[] { 1 }).eval();
                    Assert.AreEqual(new[] { 2.0, 5.0 }, c);

                    double[,] d = (double[, ])K.mean(x, axis: new int[] { }).eval();
                    Assert.AreEqual(new double[, ] {
                        { 1, 2, 3 }, { 4, 5, 6 }
                    }, d);
                }

                {
                    double[] a = (double[])K.mean(x, axis: -1).eval();
                    Assert.AreEqual(new[] { 2, 5 }, a);

                    double[] b = (double[])K.mean(x, axis: 0).eval();
                    Assert.AreEqual(new[] { 2.5, 3.5, 4.5 }, b);

                    double[] c = (double[])K.mean(x, axis: 1).eval();
                    Assert.AreEqual(new[] { 2.0, 5.0 }, c);
                }
            }
        }