source: branches/2994-AutoDiffForIntervals/HeuristicLab.Problems.DataAnalysis.Symbolic/3.4/Interpreter/AlgebraicDouble.cs @ 17298

using System;
using System.Diagnostics;

namespace HeuristicLab.Problems.DataAnalysis.Symbolic {
  // algebraic type wrapper for a double value
  [DebuggerDisplay("{Value}")]
  public sealed class AlgebraicDouble : IAlgebraicType<AlgebraicDouble> {
    public static implicit operator AlgebraicDouble(double value) { return new AlgebraicDouble(value); }
    public static implicit operator double(AlgebraicDouble value) { return value.Value; }
    public double Value;

    [DebuggerBrowsable(DebuggerBrowsableState.Never)]
    public AlgebraicDouble Zero => new AlgebraicDouble(0.0);
    [DebuggerBrowsable(DebuggerBrowsableState.Never)]
    public AlgebraicDouble One => new AlgebraicDouble(1.0);

    public bool IsInfinity => IsNegativeInfinity || IsPositiveInfinity;
    public bool IsNegativeInfinity => double.IsNegativeInfinity(Value);
    public bool IsPositiveInfinity => double.IsPositiveInfinity(Value);
    public AlgebraicDouble() { }
    public AlgebraicDouble(double value) { this.Value = value; }
    public AlgebraicDouble Assign(AlgebraicDouble a) { Value = a.Value; return this; }
    public AlgebraicDouble Add(AlgebraicDouble a) { Value += a.Value; return this; }
    public AlgebraicDouble Sub(AlgebraicDouble a) { Value -= a.Value; return this; }
    public AlgebraicDouble Mul(AlgebraicDouble a) { Value *= a.Value; return this; }
    public AlgebraicDouble Div(AlgebraicDouble a) { Value /= a.Value; return this; }
    public AlgebraicDouble Scale(double s) { Value *= s; return this; }
    public AlgebraicDouble AssignInv(AlgebraicDouble a) { Value = 1.0 / a.Value; return this; }
    public AlgebraicDouble AssignNeg(AlgebraicDouble a) { Value = -a.Value; return this; }
    public AlgebraicDouble AssignSin(AlgebraicDouble a) { Value = Math.Sin(a.Value); return this; }
    public AlgebraicDouble AssignCos(AlgebraicDouble a) { Value = Math.Cos(a.Value); return this; }
    public AlgebraicDouble AssignTanh(AlgebraicDouble a) { Value = Math.Tanh(a.Value); return this; }
    public AlgebraicDouble AssignLog(AlgebraicDouble a) { Value = Math.Log(a.Value); return this; }
    public AlgebraicDouble AssignExp(AlgebraicDouble a) { Value = Math.Exp(a.Value); return this; }
    public AlgebraicDouble AssignIntPower(AlgebraicDouble a, int p) { Value = Math.Pow(a.Value, p); return this; }
    public AlgebraicDouble AssignIntRoot(AlgebraicDouble a, int r) { Value = IntRoot(a.Value, r); return this; }
    public AlgebraicDouble AssignMin(AlgebraicDouble other) { Value = Math.Min(Value, other.Value); return this; }
    public AlgebraicDouble AssignMax(AlgebraicDouble other) { Value = Math.Max(Value, other.Value); return this; }
    public AlgebraicDouble AssignAbs(AlgebraicDouble a) { Value = Math.Abs(a.Value); return this; }
    public AlgebraicDouble AssignSgn(AlgebraicDouble a) { Value = double.IsNaN(a.Value) ? double.NaN : Math.Sign(a.Value); return this; }

    // helper
    private static double IntRoot(double value, int r) {
      if (r % 2 == 0) return Math.Pow(value, 1.0 / r);
      else return value < 0 ? -Math.Pow(-value, 1.0 / r) : Math.Pow(value, 1.0 / r);
    }

    public AlgebraicDouble Clone() { return new AlgebraicDouble(Value); }

    public override string ToString() {
      return Value.ToString();
    }
  }
}