C# Distributions.Normal类代码示例

 public void NullRandomNumberGenerator()
 {
     var random = MersenneTwister.Default;
     var normal = new Normal(0.0, 1.0, random);
     var ms = new MetropolisHastingsSampler<double>(0.2, normal.Density, (x, y) => Normal.PDF(x, 0.1, y), x => Normal.Sample(random, x, 0.1), 10);
     Assert.That(() => ms.RandomSource = null, Throws.TypeOf<ArgumentNullException>());
 }

        public void TestRidge()
        {
            var rng = new Random(0);
            const double alpha = 1.0;

            foreach (var solver in new[] { RidgeSolver.Svd, RidgeSolver.DenseCholesky, RidgeSolver.Lsqr })
            {
                // With more samples than features
                int nSamples = 6;
                int nFeatures = 5;
                var normal = new Normal { RandomSource = rng };
                Vector y = DenseVector.CreateRandom(nSamples, normal);
                Matrix x = DenseMatrix.CreateRandom(nSamples, nFeatures, normal);

                var ridge = new RidgeRegression(alpha: alpha, solver: solver);
                ridge.Fit(x, y);
                Assert.AreEqual(ridge.Coef.Row(0).Count, x.ColumnCount);
                Assert.IsTrue(ridge.Score(x, y) > 0.47);

                ridge.Fit(x, y, sampleWeight: DenseVector.Create(nSamples, i => 1.0));
                Assert.IsTrue(ridge.Score(x, y) > 0.47);

                // With more features than samples
                nSamples = 5;
                nFeatures = 10;
                y = DenseVector.CreateRandom(nSamples, normal);
                x = DenseMatrix.CreateRandom(nSamples, nFeatures, normal);
                ridge = new RidgeRegression(alpha: alpha, solver: solver);
                ridge.Fit(x, y);
                Assert.IsTrue(ridge.Score(x, y) > 0.9);

                ridge.Fit(x, y, sampleWeight: DenseVector.Create(nSamples, i => 1.0));
                Assert.IsTrue(ridge.Score(x, y) > 0.9);
            }
        }

		/// <summary>Initializes one row of a float matrix with normal distributed (Gaussian) noise</summary>
		/// <param name="matrix">the matrix to initialize</param>
		/// <param name="row">the row to be initialized</param>
		/// <param name="mean">the mean of the normal distribution drawn from</param>
		/// <param name="stddev">the standard deviation of the normal distribution</param>
		static public void RowInitNormal(this Matrix<float> matrix, int row, double mean, double stddev)
		{
			var nd = new Normal(mean, stddev);
			nd.RandomSource = MyMediaLite.Random.GetInstance();

			for (int j = 0; j < matrix.dim2; j++)
				matrix[row, j] = (float) nd.Sample();
		}

		/// <summary>Initializes a float matrix with normal distributed (Gaussian) noise</summary>
		/// <param name="matrix">the matrix to initialize</param>
		/// <param name="mean">the mean of the normal distribution drawn from</param>
		/// <param name="stddev">the standard deviation of the normal distribution</param>
		static public void InitNormal(this Matrix<float> matrix, double mean, double stddev)
		{
			var nd = new Normal(mean, stddev);
			nd.RandomSource = MyMediaLite.Random.GetInstance();

			for (int i = 0; i < matrix.data.Length; i++)
				matrix.data[i] = (float) nd.Sample();
		}

        /// <summary>Initializes one column of a double matrix with normal distributed (Gaussian) noise</summary>
        /// <param name="matrix">the matrix to initialize</param>
        /// <param name="mean">the mean of the normal distribution drawn from</param>
        /// <param name="stddev">the standard deviation of the normal distribution</param>
        /// <param name="column">the column to be initialized</param>
        public static void ColumnInitNormal(this Matrix<double> matrix, int column, double mean, double stddev)
        {
            var nd = new Normal(mean, stddev);
            nd.RandomSource = Util.Random.GetInstance();

            for (int i = 0; i < matrix.dim1; i++)
                matrix[i, column] = nd.Sample();
        }

		/// <summary>Initialize a collection of floats with values from a normal distribution</summary>
		/// <param name="vector">the vector to initialize</param>
		/// <param name="mean">the mean of the normal distribution</param>
		/// <param name="stddev">the standard deviation of the normal distribution</param>
		static public void InitNormal(this IList<float> vector, double mean, double stddev)
		{
			var nd = new Normal(mean, stddev);
			nd.RandomSource = MyMediaLite.Random.GetInstance();

			for (int i = 0; i < vector.Count; i++)
				vector[i] = (float) nd.Sample();
		}

		/// <summary>Initializes one column of a float matrix with normal distributed (Gaussian) noise</summary>
		/// <param name="matrix">the matrix to initialize</param>
		/// <param name="mean">the mean of the normal distribution drawn from</param>
		/// <param name="stddev">the standard deviation of the normal distribution</param>
		/// <param name="column">the column to be initialized</param>
		static public void ColumnInitNormal(this Matrix<float> matrix, int column, double mean, double stddev)
		{
			var nd = new Normal(mean, stddev);
			nd.RandomSource = MyMediaLite.Random.GetInstance();

			for (int i = 0; i < matrix.dim1; i++)
				matrix[i, column] = (float) nd.Sample();
		}

        public override void Initialize(List<Agent> agents)
        {
            var appSettings = ConfigurationManager.AppSettings;
            var activityMean = int.Parse(appSettings["RegularAgentActivityMean"]);
            var activityStd = int.Parse(appSettings["RegularAgentActivityStd"]);
            var distribution = new Normal(activityMean, activityStd);
            var interval = distribution.Sample();
            ActivityInterval = (int)interval;

            var contactsMean = int.Parse(appSettings["RegularAgentContactsMean"]);
            var contactsStd = int.Parse(appSettings["RegularAgentContactsStd"]);
            distribution = new Normal(contactsMean, contactsStd);
            var contactsNumber = 0;
            while (contactsNumber == 0)
            {
                contactsNumber = (int)distribution.Sample();
            }
            var strongConnectionsMean = int.Parse(appSettings["RegularAgentStrongConnectionsMean"]);
            var strongConnectionsStd = int.Parse(appSettings["RegularAgentStrongConnectionsStd"]);
            distribution = new Normal(strongConnectionsMean, strongConnectionsStd);
            var strongConnectionsNumber = (int)distribution.Sample();
            var strongConnectionsInterval = 0.75 / strongConnectionsNumber;
            var strongConnectionsIntervalMin = 0.8 * strongConnectionsInterval;
            var strongConnectionsIntervalDiff = strongConnectionsInterval - strongConnectionsIntervalMin;

            var random = new Random();
            var total = 1.0;
            var usedIndices = new List<int>();
            for (int i = 0; i < contactsNumber; i++)
            {
                var currentAgentIndex = random.Next(agents.Count);
                if (usedIndices.Contains(currentAgentIndex))
                {
                    i--;
                    continue;
                }
                usedIndices.Add(currentAgentIndex);
                var currentAgent = agents.ElementAt(currentAgentIndex);
                var probability = 0.0;
                if (i < strongConnectionsNumber)
                {
                    probability = strongConnectionsIntervalMin + random.NextDouble() * strongConnectionsIntervalDiff;
                }
                else
                {
                    if(i == contactsNumber - 1)
                    {
                        probability = total;
                    }
                    else
                    {
                        probability = 0.2 * total;
                    }
                }
                total -= probability;
                Contacts.Add(currentAgent, probability);
            }
        }

 public RandomLiquidityMaker(IRandomNumberGenerator randomNumberGenerator, double maxOrderSize, double maxPriceDifferential, double doNothingProbability, Normal normalDist,int decimals)
 {
     _rng = randomNumberGenerator;
     _maxOrderSize = maxOrderSize;
     _maxPriceDifferential = maxPriceDifferential;
     _doNothingProbability = doNothingProbability;
     _normal = normalDist;
     _decimals = decimals;
 }

        public void SampleTest()
        {
            var normal = new Normal(0.0, 1.0);
            var rnd = new MersenneTwister();

            var ms = new MetropolisSampler<double>(0.2, normal.Density, x => Normal.Sample(rnd, x, 0.1), 10);
            ms.RandomSource = rnd;

            double sample = ms.Sample();
        }

        public static IEnumerable<float> TestData()
        {
            var g = new Normal(0.0, 1.0);
            var randy = new MersenneTwister();

            g.RandomSource = randy;
            var dbls = new double[100000];
            g.Samples(dbls);
            return dbls.Select(d => (float) d);
        }

        private void CreateNormalFromString(string distributionString)
        {
            var regex = new Regex(@"Normal\(\s*(\d+)\s*,\s*(\d+)\s*\)", RegexOptions.IgnoreCase);

            var match = regex.Match(distributionString);

            var mean = double.Parse(match.Groups[1].Value);
            var stddev = double.Parse(match.Groups[2].Value);

            _normal = new Normal(mean, stddev);
        }

        public void build_prob_map()
        {
            Normal N_x = new Normal(X / 2, STD_X);
            Normal N_y = new Normal(Y / 2, STD_Y);

            DenseMatrix M_x = new DenseMatrix(Y, X, 0.0);
            DenseMatrix M_y = new DenseMatrix(Y, X, 0.0);

            DenseVector V_x = new DenseVector(X);
            for (int i = 0; i < X; i++)
            {
                V_x[i] = N_x.Density(i);
            }

            for (int j = 0; j < Y; j++)
            {
                M_x.SetRow(j, V_x);
            }

            DenseVector V_y = new DenseVector(Y);
            for (int i = 0; i < Y; i++)
            {
                V_y[i] = N_y.Density(i);
            }

            for (int j = 0; j < X; j++)
            {
                M_y.SetColumn(j, V_y);
            }

            DenseMatrix MULT = (DenseMatrix)M_x.PointwiseMultiply(M_y);
            double s = MULT.Data.Sum();
            MULT = (DenseMatrix)MULT.PointwiseDivide(new DenseMatrix(Y, X, s));
            //this.dataGridView1.DataSource = MULT;
            //Console.WriteLine(MULT.Data.Sum());
            PROB_MAP_ORIG = MULT;

            s = MULT[Y / 2, X / 2];
            MULT = (DenseMatrix)MULT.PointwiseDivide(new DenseMatrix(Y, X, s));

            /*
            for (int i = 0; i < Y; i++)
            {
                Console.Write(i + " - ");
                for (int j = 0; j < X; j++)
                {
                    Console.Write(MULT[i, j] + " ");
                }
                Console.WriteLine();
                Console.WriteLine();
            }
            */
            PROB_MAP = MULT;
        }

        public void MetropolisConstructor()
        {
            var normal = new Normal(0.0, 1.0);
            var rnd = new MersenneTwister();

            var ms = new MetropolisSampler<double>(0.2, normal.Density, x => Normal.Sample(rnd, x, 0.1), 10);
            Assert.IsNotNull(ms.RandomSource);

            ms.RandomSource = rnd;
            Assert.IsNotNull(ms.RandomSource);
        }

        public void SampleTest()
        {
            var normal = new Normal(0.0, 1.0);
            var rnd = new SystemRandomSource(1);

            var ms = new MetropolisSampler<double>(0.2, normal.Density, x => Normal.Sample(rnd, x, 0.1), 10)
                {
                    RandomSource = rnd
                };

            ms.Sample();
        }