public override void ShakeLocalParameters(IRandom random, double shakingFactor)
{
// 50% additive & 50% multiplicative (override of functionality of base class because of a BUG)
if (random.NextDouble() < 0.5)
{
double x = NormalDistributedRandom.NextDouble(random, Symbol.WeightManipulatorMu, Symbol.WeightManipulatorSigma);
Weight = Weight + x * shakingFactor;
}
else
{
double x = NormalDistributedRandom.NextDouble(random, 1.0, Symbol.MultiplicativeWeightManipulatorSigma);
Weight = Weight * x;
}
if (random.NextDouble() < Symbol.VariableChangeProbability)
{
var oldName = VariableName;
VariableName = Symbol.VariableNames.SampleRandom(random);
// reinitialize weights if variable has changed (similar to FactorVariableTreeNode)
if (oldName != VariableName)
{
Weight = NormalDistributedRandom.NextDouble(random, Symbol.WeightMu, Symbol.WeightSigma);
}
}
variableValue = Symbol.GetVariableValues(VariableName).SampleRandom(random);
}
/// <summary>
/// Performs an adaptive normally distributed all position manipulation on the given
/// <paramref name="vector"/> and rounding the results to the next feasible value.
/// </summary>
/// <exception cref="InvalidOperationException">Thrown when the strategy vector is not
/// as long as the vector to get manipulated.</exception>
/// <param name="strategyParameters">The strategy vector determining the strength of the mutation.</param>
/// <param name="random">A random number generator.</param>
/// <param name="vector">The integer vector to manipulate.</param>
/// <param name="bounds">The bounds and step size for each dimension (will be cycled in case there are less rows than elements in the parent vectors).</param>
public static void Apply(IRandom random, IntegerVector vector, IntMatrix bounds, DoubleArray strategyParameters)
{
if (strategyParameters == null || strategyParameters.Length == 0)
{
throw new ArgumentException("SelfAdaptiveRoundedNormalAllPositionsManipulator: Vector containing the standard deviations is not defined.", "sigma");
}
if (bounds == null || bounds.Rows == 0 || bounds.Columns < 2)
{
throw new ArgumentException("SelfAdaptiveRoundedNormalAllPositionsManipulator: Invalid bounds specified.", "bounds");
}
var N = new NormalDistributedRandom(random, 0.0, 1.0);
if (strategyParameters != null)
{
for (int i = 0; i < vector.Length; i++)
{
int min = bounds[i % bounds.Rows, 0], max = bounds[i % bounds.Rows, 1], step = 1;
if (bounds.Columns > 2)
{
step = bounds[i % bounds.Rows, 2];
}
int value = (vector[i] + (int)Math.Round((N.NextDouble() * strategyParameters[i % strategyParameters.Length])) - min) / step;
max = FloorFeasible(min, max, step, max - 1);
vector[i] = RoundFeasible(min, max, step, value);
}
}
}
protected override List <List <double> > GenerateValues()
{
List <List <double> > data = new List <List <double> >();
for (int i = 0; i < AllowedInputVariables.Count(); i++)
{
data.Add(ValueGenerator.GenerateUniformDistributedValues(10000, 0, 1).ToList());
}
double x1, x2, x3, x4, x5;
double f;
List <double> results = new List <double>();
for (int i = 0; i < data[0].Count; i++)
{
x1 = data[0][i];
x2 = data[1][i];
x3 = data[2][i];
x4 = data[3][i];
x5 = data[4][i];
f = 10 * Math.Sin(Math.PI * x1 * x2) + 20 * Math.Pow(x3 - 0.5, 2) + 10 * x4 + 5 * x5;
results.Add(f + NormalDistributedRandom.NextDouble(rand, 0, 1));
}
data.Add(results);
return(data);
}
/// <summary>
/// Generates a new random real vector normally distributed around the given mean with the given <paramref name="length"/> and in the interval [min,max).
/// </summary>
/// <exception cref="ArgumentException">
/// Thrown when <paramref name="random"/> is null.<br />
/// Thrown when <paramref name="mean"/> is null or of length 0.<br />
/// Thrown when <paramref name="sigma"/> is null or of length 0.<br />
/// </exception>
/// <remarks>
/// If no bounds are given the bounds will be set to (double.MinValue;double.MaxValue).
///
/// If dimensions of the mean do not lie within the given bounds they're set to either to the min or max of the bounds depending on whether the given dimension
/// for the mean is smaller or larger than the bounds. If min and max for a certain dimension are almost the same the resulting value will be set to min.
///
/// However, please consider that such static bounds are not really meaningful to optimize.
///
/// The sigma vector can contain 0 values in which case the dimension will be exactly the same as the given mean.
/// </remarks>
/// <param name="random">The random number generator.</param>
/// <param name="means">The mean vector around which the resulting vector is sampled.</param>
/// <param name="sigmas">The vector of standard deviations, must have at least one row.</param>
/// <param name="bounds">The lower and upper bound (1st and 2nd column) of the positions in the vector. If there are less rows than dimensions, the rows are cycled.</param>
/// <param name="maximumTries">The maximum number of tries to sample a value inside the bounds for each dimension. If a valid value cannot be obtained, the mean will be used.</param>
/// <returns>The newly created real vector.</returns>
public static RealVector Apply(IntValue lengthValue, IRandom random, RealVector means, DoubleArray sigmas, DoubleMatrix bounds, int maximumTries = 1000)
{
if (lengthValue == null || lengthValue.Value == 0)
{
throw new ArgumentException("Length is not defined or zero");
}
if (random == null)
{
throw new ArgumentNullException("Random is not defined", "random");
}
if (means == null || means.Length == 0)
{
throw new ArgumentNullException("Mean is not defined", "mean");
}
if (sigmas == null || sigmas.Length == 0)
{
throw new ArgumentNullException("Sigma is not defined.", "sigma");
}
if (bounds == null || bounds.Rows == 0)
{
bounds = new DoubleMatrix(new[, ] {
{ double.MinValue, double.MaxValue }
});
}
var length = lengthValue.Value;
var nd = new NormalDistributedRandom(random, 0, 1);
var result = new RealVector(length);
for (int i = 0; i < result.Length; i++)
{
var min = bounds[i % bounds.Rows, 0];
var max = bounds[i % bounds.Rows, 1];
var mean = means[i % means.Length];
var sigma = sigmas[i % sigmas.Length];
if (min.IsAlmost(max) || mean < min)
{
result[i] = min;
}
else if (mean > max)
{
result[i] = max;
}
else
{
int count = 0;
bool inRange;
do
{
result[i] = mean + sigma * nd.NextDouble();
inRange = result[i] >= min && result[i] < max;
count++;
} while (count < maximumTries && !inRange);
if (count == maximumTries && !inRange)
{
result[i] = mean;
}
}
}
return(result);
}
protected override List <List <double> > GenerateValues()
{
List <List <double> > data = new List <List <double> >();
for (int i = 0; i < AllowedInputVariables.Count(); i++)
{
data.Add(ValueGenerator.GenerateUniformDistributedValues(10000, 0, 1).ToList());
}
double x1, x2, x3, x4, x5;
double f;
List <double> results = new List <double>();
for (int i = 0; i < data[0].Count; i++)
{
x1 = data[0][i];
x2 = data[1][i];
x3 = data[2][i];
x4 = data[3][i];
x5 = data[4][i];
f = 0.1 * Math.Exp(4 * x1) + 4 / (1 + Math.Exp(-20 * (x2 - 0.5))) + 3 * x3 + 2 * x4 + x5;
results.Add(f + NormalDistributedRandom.NextDouble(rand, 0, 1));
}
data.Add(results);
return(data);
}
/// <summary>
/// <para>Sample a value from a gamma distribution.</para>
/// <para>Implementation of "A Simple Method for Generating Gamma Variables" - Marsaglia & Tsang
/// ACM Transactions on Mathematical Software, Vol. 26, No. 3, September 2000, Pages 363–372.</para>
/// </summary>
/// <param name="uniformRandom">A uniformly-distributed random number generator.</param>
/// <param name="shape">The shape (k, α) of the Gamma distribution. Range: α ≥ 0.</param>
/// <param name="rate">The rate or inverse scale (β) of the Gamma distribution. Range: β ≥ 0.</param>
/// <returns>A sample from a Gamma distributed random variable.</returns>
public static double NextDouble(IRandom uniformRandom, double shape, double rate)
{
if (double.IsPositiveInfinity(rate))
{
return(shape);
}
var a = 1d;
if (shape < 1)
{
a = Math.Pow(uniformRandom.NextDouble(), 1 / shape);
shape += 1;
}
var d = shape - 1d / 3d;
var c = 1 / Math.Sqrt(9 * d);
for (;;)
{
double v, x;
do
{
x = NormalDistributedRandom.NextDouble(uniformRandom, 0, 1);
v = 1 + c * x;
} while (v <= 0);
v = v * v * v;
x = x * x; // save a multiplication below
var u = uniformRandom.NextDouble();
if (u < 1 - 0.0331 * x * x || Math.Log(u) < 0.5 * x + d * (1 - v + Math.Log(v)))
{
return(a * d * v / rate);
}
}
}
public override void ShakeLocalParameters(IRandom random, double shakingFactor)
{
// mutate only one randomly selected weight
var idx = random.Next(weights.Length);
// 50% additive & 50% multiplicative
if (random.NextDouble() < 0.5)
{
double x = NormalDistributedRandom.NextDouble(random, Symbol.WeightManipulatorMu,
Symbol.WeightManipulatorSigma);
weights[idx] = weights[idx] + x * shakingFactor;
}
else
{
double x = NormalDistributedRandom.NextDouble(random, 1.0, Symbol.MultiplicativeWeightManipulatorSigma);
weights[idx] = weights[idx] * x;
}
if (random.NextDouble() < Symbol.VariableChangeProbability)
{
VariableName = Symbol.VariableNames.SampleRandom(random);
if (weights.Length != Symbol.GetVariableValues(VariableName).Count())
{
// if the length of the weight array does not match => re-initialize weights
weights =
Symbol.GetVariableValues(variableName)
.Select(_ => NormalDistributedRandom.NextDouble(random, 0, 1))
.ToArray();
}
}
}
private List <List <double> > CreateVariables(List <List <double> > allowedInputs, int numVars, List <string[]> inputVarNames, List <string> description, List <double[]> relevances)
{
var newVariables = new List <List <double> >();
for (int c = 0; c < numVars; c++)
{
string[] selectedVarNames;
double[] relevance;
var x = GenerateRandomFunction(random, allowedInputs, out selectedVarNames, out relevance).ToArray();
// standardize x
var sigma = x.StandardDeviation();
var mean = x.Average();
for (int i = 0; i < x.Length; i++)
{
x[i] = (x[i] - mean) / sigma;
}
var noisePrng = new NormalDistributedRandom(random, 0, Math.Sqrt(noiseRatio / (1.0 - noiseRatio)));
newVariables.Add(x.Select(t => t + noisePrng.NextDouble()).ToList());
Array.Sort(selectedVarNames, relevance);
inputVarNames.Add(selectedVarNames);
relevances.Add(relevance);
var desc = string.Format("f({0})", string.Join(",", selectedVarNames));
// for the relevance information order variables by decreasing relevance
var relevanceStr = string.Join(", ",
selectedVarNames.Zip(relevance, Tuple.Create)
.OrderByDescending(t => t.Item2)
.Select(t => string.Format(CultureInfo.InvariantCulture, "{0}: {1:N3}", t.Item1, t.Item2)));
description.Add(string.Format(" ~ N({0}, {1:N3}) [Relevances: {2}]", desc, noisePrng.Sigma, relevanceStr));
}
return(newVariables);
}
/// <summary>
/// Mutates the endogenous strategy parameters.
/// </summary>
/// <param name="random">The random number generator to use.</param>
/// <param name="vector">The strategy vector to manipulate.</param>
/// <param name="generalLearningRate">The general learning rate dampens the mutation over all dimensions.</param>
/// <param name="learningRate">The learning rate dampens the mutation in each dimension.</param>
/// <param name="bounds">The minimal and maximal value for each component, bounds are cycled if the length of bounds is smaller than the length of vector</param>
public static void Apply(IRandom random, RealVector vector, double generalLearningRate, double learningRate, DoubleMatrix bounds)
{
NormalDistributedRandom N = new NormalDistributedRandom(random, 0.0, 1.0);
double generalMultiplier = Math.Exp(generalLearningRate * N.NextDouble());
for (int i = 0; i < vector.Length; i++)
{
double change = vector[i] * generalMultiplier *Math.Exp(learningRate *N.NextDouble());
if (bounds != null)
{
double min = bounds[i % bounds.Rows, 0], max = bounds[i % bounds.Rows, 1];
if (min == max)
{
vector[i] = min;
}
else
{
while (change < min || change > max)
{
change = vector[i] * generalMultiplier *Math.Exp(learningRate *N.NextDouble());
}
vector[i] = change;
}
}
}
}
public void Mutate(NormalDistributedRandom gauss)
{
//sampling a random z from N(0,I) where I is the Identity matrix;
lastZ = new RealVector(Mean.Length);
var n = lastZ.Length;
for (var i = 0; i < n; i++)
{
lastZ[i] = gauss.NextDouble();
}
//Matrixmultiplication: lastStep = lowerCholesky * lastZ;
lastStep = new RealVector(Mean.Length);
for (var i = 0; i < n; i++)
{
double sum = 0;
for (var j = 0; j <= i; j++)
{
sum += lowerCholesky[i, j] * lastZ[j];
}
lastStep[i] = sum;
}
//add the step to x weighted by stepsize;
for (var i = 0; i < Mean.Length; i++)
{
Mean[i] += sigma * lastStep[i];
}
}
public override void ResetLocalParameters(IRandom random)
{
base.ResetLocalParameters(random);
variableName = Symbol.VariableNames.SampleRandom(random);
weights =
Symbol.GetVariableValues(variableName)
.Select(_ => NormalDistributedRandom.NextDouble(random, 0, 1)).ToArray();
}
public override void ResetLocalParameters(IRandom random)
{
base.ResetLocalParameters(random);
weight = NormalDistributedRandom.NextDouble(random, Symbol.WeightMu, Symbol.WeightSigma);
#pragma warning disable 612, 618
variableName = Symbol.VariableNames.SelectRandom(random);
#pragma warning restore 612, 618
}
/// <summary>
/// Generates normally distributed values sampling from N(mu, sigma)
/// </summary>
/// <param name="seed">The seed for the random number generator</param>
/// <param name="n">Number of values to generate.</param>
/// <param name="mu">The mu parameter of the normal distribution</param>
/// <param name="sigma">The sigma parameter of the normal distribution</param>
/// <returns>An enumerable including n values ~ N(mu, sigma)</returns>
public static IEnumerable <double> GenerateNormalDistributedValues(int seed, int n, double mu, double sigma)
{
var rand = new FastRandom(seed);
for (int i = 0; i < n; i++)
{
yield return(NormalDistributedRandom.NextDouble(rand, mu, sigma));
}
}
public override void ResetLocalParameters(IRandom random)
{
base.ResetLocalParameters(random);
threshold = NormalDistributedRandom.NextDouble(random, Symbol.ThresholdInitializerMu, Symbol.ThresholdInitializerSigma);
#pragma warning disable 612, 618
variableName = Symbol.VariableNames.SelectRandom(random);
#pragma warning restore 612, 618
slope = NormalDistributedRandom.NextDouble(random, Symbol.SlopeInitializerMu, Symbol.SlopeInitializerSigma);
}
private static IEnumerable <double> EvaluateModelWithReplacedVariable(IRegressionModel model, string variable, ModifiableDataset dataset, IEnumerable <int> rows, ReplacementMethodEnum replacement = ReplacementMethodEnum.Median)
{
var originalValues = dataset.GetReadOnlyDoubleValues(variable).ToList();
double replacementValue;
List <double> replacementValues;
IRandom rand;
switch (replacement)
{
case ReplacementMethodEnum.Median:
replacementValue = rows.Select(r => originalValues[r]).Median();
replacementValues = Enumerable.Repeat(replacementValue, dataset.Rows).ToList();
break;
case ReplacementMethodEnum.Average:
replacementValue = rows.Select(r => originalValues[r]).Average();
replacementValues = Enumerable.Repeat(replacementValue, dataset.Rows).ToList();
break;
case ReplacementMethodEnum.Shuffle:
// new var has same empirical distribution but the relation to y is broken
rand = new FastRandom(31415);
// prepare a complete column for the dataset
replacementValues = Enumerable.Repeat(double.NaN, dataset.Rows).ToList();
// shuffle only the selected rows
var shuffledValues = rows.Select(r => originalValues[r]).Shuffle(rand).ToList();
int i = 0;
// update column values
foreach (var r in rows)
{
replacementValues[r] = shuffledValues[i++];
}
break;
case ReplacementMethodEnum.Noise:
var avg = rows.Select(r => originalValues[r]).Average();
var stdDev = rows.Select(r => originalValues[r]).StandardDeviation();
rand = new FastRandom(31415);
// prepare a complete column for the dataset
replacementValues = Enumerable.Repeat(double.NaN, dataset.Rows).ToList();
// update column values
foreach (var r in rows)
{
replacementValues[r] = NormalDistributedRandom.NextDouble(rand, avg, stdDev);
}
break;
default:
throw new ArgumentException(string.Format("ReplacementMethod {0} cannot be handled.", replacement));
}
return(EvaluateModelWithReplacedVariable(model, variable, dataset, rows, replacementValues));
}
private static IList GetReplacementValuesForDouble(ModifiableDataset modifiableDataset,
IEnumerable <int> rows,
List <double> originalValues,
ReplacementMethodEnum replacementMethod = ReplacementMethodEnum.Shuffle)
{
IRandom random = new FastRandom(31415);
List <double> replacementValues;
double replacementValue;
switch (replacementMethod)
{
case ReplacementMethodEnum.Median:
replacementValue = rows.Select(r => originalValues[r]).Median();
replacementValues = Enumerable.Repeat(replacementValue, modifiableDataset.Rows).ToList();
break;
case ReplacementMethodEnum.Average:
replacementValue = rows.Select(r => originalValues[r]).Average();
replacementValues = Enumerable.Repeat(replacementValue, modifiableDataset.Rows).ToList();
break;
case ReplacementMethodEnum.Shuffle:
// new var has same empirical distribution but the relation to y is broken
// prepare a complete column for the dataset
replacementValues = Enumerable.Repeat(double.NaN, modifiableDataset.Rows).ToList();
// shuffle only the selected rows
var shuffledValues = rows.Select(r => originalValues[r]).Shuffle(random).ToList();
int i = 0;
// update column values
foreach (var r in rows)
{
replacementValues[r] = shuffledValues[i++];
}
break;
case ReplacementMethodEnum.Noise:
var avg = rows.Select(r => originalValues[r]).Average();
var stdDev = rows.Select(r => originalValues[r]).StandardDeviation();
// prepare a complete column for the dataset
replacementValues = Enumerable.Repeat(double.NaN, modifiableDataset.Rows).ToList();
// update column values
foreach (var r in rows)
{
replacementValues[r] = NormalDistributedRandom.NextDouble(random, avg, stdDev);
}
break;
default:
throw new ArgumentException(string.Format("ReplacementMethod {0} cannot be handled.", replacementMethod));
}
return(replacementValues);
}
/// <summary>
/// Performs an adaptive normally distributed all position manipulation on the given
/// <paramref name="vector"/>.
/// </summary>
/// <exception cref="InvalidOperationException">Thrown when the strategy vector is not
/// as long as the vector to get manipulated.</exception>
/// <param name="sigma">The strategy vector determining the strength of the mutation.</param>
/// <param name="random">A random number generator.</param>
/// <param name="vector">The real vector to manipulate.</param>
/// <returns>The manipulated real vector.</returns>
public static void Apply(IRandom random, RealVector vector, RealVector sigma)
{
if (sigma == null || sigma.Length == 0)
{
throw new ArgumentException("ERROR: Vector containing the standard deviations is not defined.", "sigma");
}
NormalDistributedRandom N = new NormalDistributedRandom(random, 0.0, 1.0);
for (int i = 0; i < vector.Length; i++)
{
vector[i] = vector[i] + (N.NextDouble() * sigma[i % sigma.Length]);
}
}
public override void ShakeLocalParameters(IRandom random, double shakingFactor)
{
base.ShakeLocalParameters(random, shakingFactor);
double x = NormalDistributedRandom.NextDouble(random, Symbol.ThresholdManipulatorMu, Symbol.ThresholdManipulatorSigma);
threshold = threshold + x * shakingFactor;
#pragma warning disable 612, 618
variableName = Symbol.VariableNames.SelectRandom(random);
#pragma warning restore 612, 618
x = NormalDistributedRandom.NextDouble(random, Symbol.SlopeManipulatorMu, Symbol.SlopeManipulatorSigma);
slope = slope + x * shakingFactor;
}
/// <summary>
/// Performs an adaptive normally distributed all position manipulation on the given
/// <paramref name="vector"/>.
/// </summary>
/// <exception cref="InvalidOperationException">Thrown when the strategy vector is not
/// as long as the vector to get manipulated.</exception>
/// <param name="strategyParameters">The strategy vector determining the strength of the mutation.</param>
/// <param name="random">A random number generator.</param>
/// <param name="vector">The real vector to manipulate.</param>
/// <returns>The manipulated real vector.</returns>
public static void Apply(IRandom random, RealVector vector, RealVector strategyParameters)
{
NormalDistributedRandom N = new NormalDistributedRandom(random, 0.0, 1.0);
if (strategyParameters != null)
{
for (int i = 0; i < vector.Length; i++)
{
vector[i] = vector[i] + (N.NextDouble() * strategyParameters[i % strategyParameters.Length]);
}
}
else
{
// BackwardsCompatibility3.3
#region Backwards compatible region (remove with 3.4)
// when upgrading to 3.4 remove the whole condition and just put the if-branch in place (you should then also throw an ArgumentException when strategyParameters is null or has length 0)
for (int i = 0; i < vector.Length; i++)
{
vector[i] = vector[i] + N.NextDouble();
}
#endregion
}
}
public override void ShakeLocalParameters(IRandom random, double shakingFactor)
{
base.ShakeLocalParameters(random, shakingFactor);
// 50% additive & 50% multiplicative
if (random.NextDouble() < 0.5)
{
double x = NormalDistributedRandom.NextDouble(random, Symbol.ManipulatorMu, Symbol.ManipulatorSigma);
Value = Value + x * shakingFactor;
}
else
{
double x = NormalDistributedRandom.NextDouble(random, 1.0, Symbol.MultiplicativeManipulatorSigma);
Value = Value * x;
}
}
public static AdditiveMove[] Apply(IRandom random, RealVector vector, double sigma, int sampleSize, DoubleMatrix bounds)
{
AdditiveMove[] moves = new AdditiveMove[sampleSize];
NormalDistributedRandom N = new NormalDistributedRandom(random, 0, sigma);
for (int i = 0; i < sampleSize; i++)
{
int index = random.Next(vector.Length);
double strength = 0, min = bounds[index % bounds.Rows, 0], max = bounds[index % bounds.Rows, 1];
do
{
strength = N.NextDouble();
} while (vector[index] + strength <min || vector[index] + strength> max);
moves[i] = new AdditiveMove(index, strength);
}
return(moves);
}
private IEnumerable <double> SampleGaussianProcess(IRandom random, List <double>[] xs)
{
int nl = xs.Length;
int nRows = xs.First().Count;
double[,] K = new double[nRows, nRows];
// sample length-scales
var l = Enumerable.Range(0, nl)
.Select(_ => random.NextDouble() * 2 + 0.5)
.ToArray();
// calculate covariance matrix
for (int r = 0; r < nRows; r++)
{
double[] xi = xs.Select(x => x[r]).ToArray();
for (int c = 0; c <= r; c++)
{
double[] xj = xs.Select(x => x[c]).ToArray();
double dSqr = xi.Zip(xj, (xik, xjk) => (xik - xjk))
.Select(dk => dk * dk)
.Zip(l, (dk, lk) => dk / lk)
.Sum();
K[r, c] = Math.Exp(-dSqr);
}
}
// add a small diagonal matrix for numeric stability
for (int i = 0; i < nRows; i++)
{
K[i, i] += 1.0E-7;
}
// decompose
alglib.trfac.spdmatrixcholesky(ref K, nRows, false);
// sample u iid ~ N(0, 1)
var u = Enumerable.Range(0, nRows).Select(_ => NormalDistributedRandom.NextDouble(random, 0, 1)).ToArray();
// calc y = Lu
var y = new double[u.Length];
alglib.ablas.rmatrixmv(nRows, nRows, K, 0, 0, 0, u, 0, ref y, 0);
return(y);
}
protected override List <List <double> > GenerateValues()
{
List <List <double> > data = new List <List <double> >();
List <int> values = new List <int>()
{
-1, 1
};
var rand = new MersenneTwister((uint)Seed);
data.Add(GenerateUniformIntegerDistribution(rand, values, TestPartitionEnd));
values.Add(0);
for (int i = 0; i < AllowedInputVariables.Count() - 1; i++)
{
data.Add(GenerateUniformIntegerDistribution(rand, values, TestPartitionEnd));
}
double x1, x2, x3, x4, x5, x6, x7;
double f;
List <double> results = new List <double>();
double sigma = Math.Sqrt(2);
for (int i = 0; i < data[0].Count; i++)
{
x1 = data[0][i];
x2 = data[1][i];
x3 = data[2][i];
x4 = data[3][i];
x5 = data[4][i];
x6 = data[5][i];
x7 = data[6][i];
if (x1.Equals(1))
{
f = 3 + 3 * x2 + 2 * x3 + x4;
}
else
{
f = -3 + 3 * x5 + 2 * x6 + x7;
}
results.Add(f + NormalDistributedRandom.NextDouble(rand, 0, sigma));
}
data.Add(results);
return(data);
}
public static void UpdateVelocity(IRandom random, RealVector velocity, RealVector position, RealVector personalBest, RealVector neighborBest, double inertia = 0.721, double personalBestAttraction = 1.193, double neighborBestAttraction = 1.193, double maxVelocity = double.MaxValue)
{
var gravity = new double[velocity.Length];
var direction = new RealVector(velocity.Length);
var radius = 0.0;
var nd = new NormalDistributedRandom(random, 0, 1);
for (int i = 0; i < velocity.Length; i++)
{
var g_id = (personalBestAttraction * personalBest[i]
+ neighborBestAttraction * neighborBest[i]
- position[i] * (neighborBestAttraction + personalBestAttraction)) / 3.0;
// center of the hyper-sphere
gravity[i] = g_id + position[i];
// a random direction vector uniform over the surface of hyper-sphere, see http://mathworld.wolfram.com/HyperspherePointPicking.html
direction[i] = nd.NextDouble();
radius += g_id * g_id;
}
// randomly choose a radius within the hyper-sphere
radius = random.NextDouble() * Math.Sqrt(radius);
// unitscale is used to rescale the random direction vector to unit length, resp. length of the radius
var unitscale = Math.Sqrt(direction.DotProduct(direction));
if (unitscale > 0)
{
for (var i = 0; i < velocity.Length; i++)
{
var sampledPos = gravity[i] + direction[i] * radius / unitscale;
velocity[i] = velocity[i] * inertia + sampledPos - position[i];
}
}
var speed = Math.Sqrt(velocity.DotProduct(velocity));
if (speed > maxVelocity)
{
for (var i = 0; i < velocity.Length; i++)
{
velocity[i] *= maxVelocity / speed;
}
}
}
public override void ShakeLocalParameters(IRandom random, double shakingFactor)
{
base.ShakeLocalParameters(random, shakingFactor);
// 50% additive & 50% multiplicative
if (random.NextDouble() < 0)
{
double x = NormalDistributedRandom.NextDouble(random, Symbol.WeightManipulatorMu, Symbol.WeightManipulatorSigma);
weight = weight + x * shakingFactor;
}
else
{
double x = NormalDistributedRandom.NextDouble(random, 1.0, Symbol.MultiplicativeWeightManipulatorSigma);
weight = weight * x;
}
#pragma warning disable 612, 618
variableName = Symbol.VariableNames.SelectRandom(random);
#pragma warning restore 612, 618
}
private static IEnumerable <double> EvaluateModelWithReplacedVariable(IRegressionModel model, string variable, ModifiableDataset dataset, IEnumerable <int> rows, ReplacementMethodEnum replacement = ReplacementMethodEnum.Median)
{
var originalValues = dataset.GetReadOnlyDoubleValues(variable).ToList();
double replacementValue;
List <double> replacementValues;
IRandom rand;
switch (replacement)
{
case ReplacementMethodEnum.Median:
replacementValue = rows.Select(r => originalValues[r]).Median();
replacementValues = Enumerable.Repeat(replacementValue, dataset.Rows).ToList();
break;
case ReplacementMethodEnum.Average:
replacementValue = rows.Select(r => originalValues[r]).Average();
replacementValues = Enumerable.Repeat(replacementValue, dataset.Rows).ToList();
break;
case ReplacementMethodEnum.Shuffle:
// new var has same empirical distribution but the relation to y is broken
rand = new FastRandom(31415);
replacementValues = rows.Select(r => originalValues[r]).Shuffle(rand).ToList();
break;
case ReplacementMethodEnum.Noise:
var avg = rows.Select(r => originalValues[r]).Average();
var stdDev = rows.Select(r => originalValues[r]).StandardDeviation();
rand = new FastRandom(31415);
replacementValues = rows.Select(_ => NormalDistributedRandom.NextDouble(rand, avg, stdDev)).ToList();
break;
default:
throw new ArgumentException(string.Format("ReplacementMethod {0} cannot be handled.", replacement));
}
dataset.ReplaceVariable(variable, replacementValues);
//mkommend: ToList is used on purpose to avoid lazy evaluation that could result in wrong estimates due to variable replacements
var estimates = model.GetEstimatedValues(dataset, rows).ToList();
dataset.ReplaceVariable(variable, originalValues);
return(estimates);
}
private IEnumerable <double> SampleLinearFunction(IRandom rand, List <double>[] xs, out double[] relevance)
{
int nl = xs.Length;
int nRows = xs.First().Count;
// sample standardized coefficients iid ~ N(0, 1)
var c = Enumerable.Range(0, nRows).Select(_ => NormalDistributedRandom.NextDouble(rand, 0, 1)).ToArray();
// calculate scaled coefficients (variables with large variance should have smaller coefficients)
var scaledC = Enumerable.Range(0, nl)
.Select(i => c[i] / xs[i].StandardDeviationPop())
.ToArray();
var y = EvaluteLinearModel(xs, scaledC);
relevance = CalculateRelevance(y, xs, scaledC);
return(y);
}
protected override List <List <double> > GenerateValues()
{
List <List <double> > data = new List <List <double> >();
var nrand = new NormalDistributedRandom(random, 0, 1);
for (int c = 0; c < numberOfFeatures; c++)
{
var datai = Enumerable.Range(0, TestPartitionEnd).Select(_ => nrand.NextDouble()).ToList();
data.Add(datai);
}
var y = GenerateRandomFunction(random, data);
var targetSigma = y.StandardDeviation();
var noisePrng = new NormalDistributedRandom(random, 0, targetSigma * Math.Sqrt(noiseRatio / (1.0 - noiseRatio)));
data.Add(y.Select(t => t + noisePrng.NextDouble()).ToList());
return(data);
}
protected override List <List <double> > GenerateValues()
{
var rand = new MersenneTwister((uint)Seed);
List <List <double> > data = new List <List <double> >();
var C_La = ValueGenerator.GenerateUniformDistributedValues(rand.Next(), TestPartitionEnd, 0.4, 0.8).ToList();
var a = ValueGenerator.GenerateUniformDistributedValues(rand.Next(), TestPartitionEnd, 5.0, 10.0).ToList();
var C_Ld_e = ValueGenerator.GenerateUniformDistributedValues(rand.Next(), TestPartitionEnd, 0.4, 0.8).ToList();
var d_e = ValueGenerator.GenerateUniformDistributedValues(rand.Next(), TestPartitionEnd, 5.0, 10.0).ToList();
var S_HT = ValueGenerator.GenerateUniformDistributedValues(rand.Next(), TestPartitionEnd, 1.0, 1.5).ToList();
var S_ref = ValueGenerator.GenerateUniformDistributedValues(rand.Next(), TestPartitionEnd, 5.0, 7.0).ToList();
var C_L = new List <double>();
var C_L_noise = new List <double>();
data.Add(C_La);
data.Add(a);
data.Add(C_Ld_e);
data.Add(d_e);
data.Add(S_HT);
data.Add(S_ref);
data.Add(C_L);
data.Add(C_L_noise);
double a0 = -2.0;
for (int i = 0; i < C_La.Count; i++)
{
double C_Li = C_La[i] * (a[i] - a0) + C_Ld_e[i] * d_e[i] * S_HT[i] / S_ref[i];
C_L.Add(C_Li);
}
var sigma_noise = 0.05 * C_L.StandardDeviationPop();
C_L_noise.AddRange(C_L.Select(md => md + NormalDistributedRandom.NextDouble(rand, 0, sigma_noise)));
return(data);
}
protected override List <List <double> > GenerateValues()
{
List <List <double> > data = new List <List <double> >();
for (int i = 0; i < AllowedInputVariables.Count(); i++)
{
data.Add(Enumerable.Range(0, TestPartitionEnd)
.Select(_ => xRandom.NextDouble())
.ToList());
}
var random = new MersenneTwister();
var selectedFeatures =
Enumerable.Range(0, AllowedInputVariables.Count())
.Where(_ => random.NextDouble() < selectionProbability)
.ToArray();
w = selectedFeatures.Select(_ => weightRandom.NextDouble()).ToArray();
var target = new List <double>();
for (int i = 0; i < data[0].Count; i++)
{
var s = selectedFeatures
.Select(index => data[index][i])
.ToArray();
target.Add(ScalarProd(s, w));
}
var targetSigma = target.StandardDeviation();
var noisePrng = new NormalDistributedRandom(random, 0, targetSigma * Math.Sqrt(noiseRatio / (1.0 - noiseRatio)));
data.Add(target.Select(t => t + noisePrng.NextDouble()).ToList());
// set property listing the selected features as string[]
this.selectedFeatures = selectedFeatures.Select(i => AllowedInputVariables[i]).ToArray();
optimalRSquared = 1 - noiseRatio;
return(data);
}