source: branches/2796_SymbReg/HeuristicLab.Algorithms.DataAnalysis/3.4/MctsSymbolicRegression/ApproximateDoubleEqualityComparer.cs @ 15683

using System;
using System.Collections.Generic;

namespace HeuristicLab.Algorithms.DataAnalysis.MctsSymbolicRegression {
  // unused?
  internal class ApproximateDoubleEqualityComparer : IEqualityComparer<double> {
    public bool Equals(double x, double y) {
      // TODO: check
      var xl = (ulong)BitConverter.DoubleToInt64Bits(x);
      var yl = (ulong)BitConverter.DoubleToInt64Bits(y);

      xl = xl & 0xFFFFFFFFFFFFFFE0; // ignore least significant bits
      yl = yl & 0xFFFFFFFFFFFFFFE0;

      return xl == yl;
    }

    public int GetHashCode(double obj) {
      var bits = (ulong)BitConverter.DoubleToInt64Bits(obj);

      bits = bits & 0xFFFFFFFFFFFFFFE0; // ignore least significant bits

      return (int)bits;
    }
  }
}