1  #region License Information


2  /* HeuristicLab


3  * Copyright (C) 20022019 Heuristic and Evolutionary Algorithms Laboratory (HEAL)


4  *


5  * This file is part of HeuristicLab.


6  *


7  * HeuristicLab is free software: you can redistribute it and/or modify


8  * it under the terms of the GNU General Public License as published by


9  * the Free Software Foundation, either version 3 of the License, or


10  * (at your option) any later version.


11  *


12  * HeuristicLab is distributed in the hope that it will be useful,


13  * but WITHOUT ANY WARRANTY; without even the implied warranty of


14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the


15  * GNU General Public License for more details.


16  *


17  * You should have received a copy of the GNU General Public License


18  * along with HeuristicLab. If not, see <http://www.gnu.org/licenses/>.


19  */


20  #endregion


21 


22  using System;


23  using System.Collections.Generic;


24  using System.Linq;


25  using HeuristicLab.Common;


26  using HeuristicLab.Random;


27 


28  namespace HeuristicLab.Problems.Instances.DataAnalysis {


29  public class FluidDynamics : ArtificialRegressionDataDescriptor {


30  public override string Name { get { return "Spinning cylinder flow Ψ = V_∞ r sin(θ) (1  R²/r²) + Γ/(2 π) ln(r/R)"; } }


31 


32  public override string Description {


33  get {


34  return "A full description of this problem instance is given in: " + Environment.NewLine +


35  "Chen Chen, Changtong Luo, Zonglin Jiang, \"A multilevel block building algorithm for fast " +


36  "modeling generalized separable systems\", Expert Systems with Applications, Volume 109, 2018, " +


37  "Pages 2534 https://doi.org/10.1016/j.eswa.2018.05.021. " + Environment.NewLine +


38  "Function: Ψ = V_∞ r sin(θ) (1  R²/r²) + Γ/(2 π) ln(r/R)" + Environment.NewLine +


39  "with uniform stream velocity V_∞ ∈ [60 m/s, 65 m/s]," + Environment.NewLine +


40  "angle for polar coordinate vector field θ ∈ [30°, 40°]," + Environment.NewLine +


41  "radius for polar coordinate vector field r ∈ [0.5m, 0.8m]," + Environment.NewLine +


42  "radius of cylinder R ∈ [0.2m, 0.5m]," + Environment.NewLine +


43  "vortex strength (induced by spinning) Γ ∈ [5 m²/s, 10 m²/s]" + Environment.NewLine +


44  "Note: the definition deviates from the definition used in the source above because here we have r > R meaning we want to calculate the flow _outside_ of the cylinder.";


45  }


46  }


47 


48  protected override string TargetVariable { get { return "Ψ"; } }


49  protected override string[] VariableNames { get { return new string[] { "V_∞", "θ", "r", "R", "Γ", "Ψ", "Ψ_noise" }; } }


50  protected override string[] AllowedInputVariables { get { return new string[] { "V_∞", "θ", "r", "R", "Γ" }; } }


51  protected override int TrainingPartitionStart { get { return 0; } }


52  protected override int TrainingPartitionEnd { get { return 100; } }


53  protected override int TestPartitionStart { get { return 100; } }


54  protected override int TestPartitionEnd { get { return 200; } }


55 


56  public int Seed { get; private set; }


57 


58  public FluidDynamics() : this((int)System.DateTime.Now.Ticks) { }


59 


60  public FluidDynamics(int seed) {


61  Seed = seed;


62  }


63 


64  protected override List<List<double>> GenerateValues() {


65  var rand = new MersenneTwister((uint)Seed);


66 


67  List<List<double>> data = new List<List<double>>();


68  var V_inf = ValueGenerator.GenerateUniformDistributedValues(rand.Next(), TestPartitionEnd, 60.0, 65.0).ToList();


69  var th = ValueGenerator.GenerateUniformDistributedValues(rand.Next(), TestPartitionEnd, 30.0, 40.0).ToList();


70  var r = ValueGenerator.GenerateUniformDistributedValues(rand.Next(), TestPartitionEnd, 0.5, 0.8).ToList();


71  var R = ValueGenerator.GenerateUniformDistributedValues(rand.Next(), TestPartitionEnd, 0.2, 0.5).ToList();


72  var G = ValueGenerator.GenerateUniformDistributedValues(rand.Next(), TestPartitionEnd, 5, 10).ToList();


73 


74  var Psi = new List<double>();


75  var Psi_noise = new List<double>();


76 


77  data.Add(V_inf);


78  data.Add(th);


79  data.Add(r);


80  data.Add(R);


81  data.Add(G);


82  data.Add(Psi);


83  data.Add(Psi_noise);


84 


85  for (int i = 0; i < V_inf.Count; i++) {


86  var th_rad = Math.PI * th[i] / 180.0;


87  double Psi_i = V_inf[i] * r[i] * Math.Sin(th_rad) * (1  (R[i] * R[i]) / (r[i] * r[i])) +


88  (G[i] / (2 * Math.PI)) * Math.Log(r[i] / R[i]);


89  Psi.Add(Psi_i);


90  }


91 


92  var sigma_noise = 0.05 * Psi.StandardDeviationPop();


93  Psi_noise.AddRange(Psi.Select(md => md + NormalDistributedRandom.NextDouble(rand, 0, sigma_noise)));


94 


95  return data;


96  }


97  }


98  }

