public void TestNorm()
        {
            var instance = new SparseIntegerVector(new[] { 0, 0, 2 });

            var result = instance.Norm();

            Assert.Equal(expected: 2.0, actual: result);
        }
        public void TestCosineSimilarity()
        {
            var other    = new SparseIntegerVector(new[] { 0, 1, 2, 3 });
            var instance = new SparseIntegerVector(new[] { 1, 2, 0, 0 });

            var expectedResult = instance.DotProduct(other) / (instance.Norm() * other.Norm());
            var result         = instance.CosineSimilarity(other);

            Assert.Equal(expected: expectedResult, actual: result);
        }