Relative-Strength-Indicator

CODE:
using WealthLab.Core;
using System;
using System.Drawing;
using WealthLab.Indicators; 
using WealthLab.ChartWPF;
using WealthLab.Backtest;

namespace WealthLab.MyIndicators
{
    public class RealRelativeStrength : IndicatorBase
    {
        //parameterless constructor
        public RealRelativeStrength() : base()
        {
        }

        //for code based construction
        public RealRelativeStrength(BarHistory source, String compareSymbol, Int32 period)
            : base()
        {
         Parameters[0].Value = source;
         Parameters[1].Value = compareSymbol;
         Parameters[2].Value = period;

            Populate();
        }

      //static Series method
      public static RealRelativeStrength Series(BarHistory source, String compareSymbol, Int32 period)
      {
         return new RealRelativeStrength(source, compareSymbol, period);
      }

        //name
        public override string Name
        {
            get
            {
                return "RealRelativeStrength";
            }
        }

        //abbreviation
        public override string Abbreviation
        {
            get
            {
                return "RRS";
            }
        }

        //description
        public override string HelpDescription
        {
            get
            {
                return "Real Relative Strength measured against a compared symbol or sector etf";
            }
        }

        //price pane
        public override string PaneTag
        {
            get
            {
                return "rrs";
            }
        }

      //default color
      public override WLColor DefaultColor
      {
         get
         {
            return WLColor.FromArgb(255,50,205,50);
         }
      }

      //default plot style
      public override PlotStyle DefaultPlotStyle
      {
         get
         {
            return PlotStyle.Oscillator;
         }
      }

        //populate
        public override void Populate()
        {
         BarHistory source = Parameters[0].AsBarHistory;
         String compareSymbol = Parameters[1].AsString;
         Int32 period = Parameters[2].AsInt;

            DateTimes = source.DateTimes;

         //modify the code below to implement your own indicator calculation


         BarHistory compSource = WLHost.Instance.GetHistory(compareSymbol, source.Scale, DateTime.MinValue, DateTime.MaxValue, source.Count, null);
         ATR compAtr = ATR.Series(compSource, period);

         if(source != null && source.Count > 0)
         {
            ATR symAtr = ATR.Series(source, period);
            TimeSeries compAtrSynced = TimeSeriesSynchronizer.Synchronize(compAtr, source);

            for (int n = 0; n < compSource.Count; n++)
            {
               if (n > period)
               {
                  double compSymRollingMove = compSource.Close[n] - compSource.Close[n - period];
                  double symRollingMove = source.Close[n] - source.Close[n - period];

                  var powerIndex = compSymRollingMove / compAtr.Values[n];
                  var rrs = (symRollingMove - powerIndex * symAtr.Values[n]) / symAtr.Values[n];

                  Values[n] = rrs;
               }
            }

         }
        }

        //generate parameters
        protected override void GenerateParameters()
        {
         AddParameter("Source", ParameterType.BarHistory, null);
         AddParameter("Compare Symbol", ParameterType.String, "SPY");
         AddParameter("Period", ParameterType.Int32, 12);
        }
    }
}