source: addons/HeuristicLab.MetaOptimization/HeuristicLab.Problems.MetaOptimization/3.3/Encoding/RangeConstraints/IntValueRange.cs

using System;
using System.Collections.Generic;
using HeuristicLab.Common;
using HeuristicLab.Core;
using HeuristicLab.Data;
using HEAL.Attic;

namespace HeuristicLab.Problems.MetaOptimization {
  [StorableType("124C6B55-A78D-4D82-810F-B5FD0C23EBB6")]
  public class IntValueRange : Range<IntValue> {

    public IntValueRange(IntValue lowerBound, IntValue upperBound, IntValue stepSize) : base(lowerBound, upperBound, stepSize) { }
    [StorableConstructor]
    protected IntValueRange(StorableConstructorFlag _) : base(_) { }
    protected IntValueRange(IntValueRange original, Cloner cloner) : base(original, cloner) { }
    public override IDeepCloneable Clone(Cloner cloner) {
      return new IntValueRange(this, cloner);
    }

    protected override IntValue GetRandomSample(IRandom random) {
      int val;
      do {
        val = random.Next(LowerBound.Value / StepSize.Value, UpperBound.Value / StepSize.Value + 1) * StepSize.Value;
      } while (!IsInRange(val));
      return new IntValue(val);
    }

    public int ApplyStepSize(int value) {
      return ((int)Math.Round(value / (double)this.StepSize.Value, 0)) * this.StepSize.Value;
    }

    public bool IsInRange(int value) {
      return value <= this.UpperBound.Value && value >= this.LowerBound.Value;
    }

    public override IEnumerable<IntValue> GetCombinations() {
      var solutions = new List<IntValue>();
      int value = this.LowerBound.Value;

      while (value <= this.UpperBound.Value) {
        solutions.Add(new IntValue(value));
        value += this.StepSize.Value;
      }
      return solutions;
    }

    protected override double CalculateSimilarityValue(IntValue a, IntValue b) {
      double range = UpperBound.Value - LowerBound.Value;
      double diff = Math.Abs(a.Value - b.Value);
      return Math.Max(0, (range - (diff * 2)) / range);
    }
  }
}