Supported Indicators

True Strength Index

Introduction

This indicator computes the True Strength Index (TSI). The True Strength Index is calculated as explained here: https://school.stockcharts.com/doku.php?id=technical_indicators:True_strength_index Briefly, the calculation has three steps: 1. Smooth the momentum and the absolute momentum by getting an EMA of them (typically of period 25) 2. Double smooth the momentum and the absolute momentum by getting an EMA of their EMA (typically of period 13) 3. The TSI formula itself: divide the double-smoothed momentum over the double-smoothed absolute momentum and multiply by 100 The signal is typically a 7-to-12-EMA of the TSI.

To view the implementation of this indicator, see the LEAN GitHub repository.

Using TSI Indicator

To create an automatic indicator for TrueStrengthIndex, call the TSItsi helper method from the QCAlgorithm class. The TSItsi method creates a TrueStrengthIndex object, hooks it up for automatic updates, and returns it so you can used it in your algorithm. In most cases, you should call the helper method in the Initializeinitialize method.

public class TrueStrengthIndexAlgorithm : QCAlgorithm
{
    private Symbol _symbol;
    private TrueStrengthIndex _tsi;

    public override void Initialize()
    {
        _symbol = AddEquity("SPY", Resolution.Daily).Symbol;
        _tsi = TSI(_symbol, 25, 13, 7, MovingAverageType.Exponential);
    }

    public override void OnData(Slice data)
    {

        if (_tsi.IsReady)
        {
            // The current value of _tsi is represented by itself (_tsi)
            // or _tsi.Current.Value
            Plot("TrueStrengthIndex", "tsi", _tsi);
            // Plot all properties of abands
            Plot("TrueStrengthIndex", "signal", _tsi.Signal);
        }
    }
}
class TrueStrengthIndexAlgorithm(QCAlgorithm):
    def initialize(self) -> None:
        self._symbol = self.add_equity("SPY", Resolution.DAILY).symbol
        self._tsi = self.tsi(self._symbol, 25, 13, 7, MovingAverageType.EXPONENTIAL)

    def on_data(self, slice: Slice) -> None:

        if self._tsi.is_ready:
            # The current value of self._tsi is represented by self._tsi.current.value
            self.plot("TrueStrengthIndex", "tsi", self._tsi.current.value)
            # Plot all attributes of self._tsi
            self.plot("TrueStrengthIndex", "signal", self._tsi.signal.current.value)

For more information about this method, see the QCAlgorithm classQCAlgorithm class.

You can manually create a TrueStrengthIndex indicator, so it doesn't automatically update. Manual indicators let you update their values with any data you choose.

Updating your indicator manually enables you to control when the indicator is updated and what data you use to update it. To manually update the indicator, call the Updateupdate method. The indicator will only be ready after you prime it with enough data.

public class TrueStrengthIndexAlgorithm : QCAlgorithm
{
    private Symbol _symbol;
    private TrueStrengthIndex _truestrengthindex;

    public override void Initialize()
    {
        _symbol = AddEquity("SPY", Resolution.Daily).Symbol;
        _truestrengthindex = new TrueStrengthIndex(25, 13, 7, MovingAverageType.Exponential);
    }

    public override void OnData(Slice data)
    {
        if (data.Bars.TryGetValue(_symbol, out var bar))
            _truestrengthindex.Update(bar.EndTime, bar.Close);

        if (_truestrengthindex.IsReady)
        {
            // The current value of _truestrengthindex is represented by itself (_truestrengthindex)
            // or _truestrengthindex.Current.Value
            Plot("TrueStrengthIndex", "truestrengthindex", _truestrengthindex);
            // Plot all properties of abands
            Plot("TrueStrengthIndex", "signal", _truestrengthindex.Signal);
        }
    }
}
class TrueStrengthIndexAlgorithm(QCAlgorithm):
    def initialize(self) -> None:
        self._symbol = self.add_equity("SPY", Resolution.DAILY).symbol
        self._truestrengthindex = TrueStrengthIndex(25, 13, 7, MovingAverageType.EXPONENTIAL)

    def on_data(self, slice: Slice) -> None:
        bar = slice.bars.get(self._symbol)
        if bar:
            self._truestrengthindex.update(bar.end_time, bar.close)

        if self._truestrengthindex.is_ready:
            # The current value of self._truestrengthindex is represented by self._truestrengthindex.current.value
            self.plot("TrueStrengthIndex", "truestrengthindex", self._truestrengthindex.current.value)
            # Plot all attributes of self._truestrengthindex
            self.plot("TrueStrengthIndex", "signal", self._truestrengthindex.signal.current.value)

For more information about this indicator, see its referencereference.

Visualization

The following plot shows values for some of the TrueStrengthIndex indicator properties:

TrueStrengthIndex line plot.

Indicator History

To get the historical data of the TrueStrengthIndex indicator, call the IndicatorHistoryself.indicator_history method. This method resets your indicator, makes a history request, and updates the indicator with the historical data. Just like with regular history requests, the IndicatorHistoryindicator_history method supports time periods based on a trailing number of bars, a trailing period of time, or a defined period of time. If you don't provide a resolution argument, it defaults to match the resolution of the security subscription. 

public class TrueStrengthIndexAlgorithm : QCAlgorithm
{
    private Symbol _symbol;
    private TrueStrengthIndex _tsi;

    public override void Initialize()
    {
        _symbol = AddEquity("SPY", Resolution.Daily).Symbol;
        _tsi = TSI(_symbol, 25, 13, 7, MovingAverageType.Exponential);

        var indicatorHistory = IndicatorHistory(_tsi, _symbol, 100, Resolution.Minute);
        var timeSpanIndicatorHistory = IndicatorHistory(_tsi, _symbol, TimeSpan.FromDays(10), Resolution.Minute);
        var timePeriodIndicatorHistory = IndicatorHistory(_tsi, _symbol, new DateTime(2024, 7, 1), new DateTime(2024, 7, 5), Resolution.Minute);

        // Access all attributes of indicatorHistory
        var signal = indicatorHistory.Select(x => ((dynamic)x).Signal).ToList();
    }
}
class TrueStrengthIndexAlgorithm(QCAlgorithm):
    def initialize(self) -> None:
        self._symbol = self.add_equity("SPY", Resolution.DAILY).symbol
        self._tsi = self.tsi(self._symbol, 25, 13, 7, MovingAverageType.EXPONENTIAL)

        indicator_history = self.indicator_history(self._tsi, self._symbol, 100, Resolution.MINUTE)
        timedelta_indicator_history = self.indicator_history(self._tsi, self._symbol, timedelta(days=10), Resolution.MINUTE)
        time_period_indicator_history = self.indicator_history(self._tsi, self._symbol, datetime(2024, 7, 1), datetime(2024, 7, 5), Resolution.MINUTE)
    
        # Access all attributes of indicator_history
        indicator_history_df = indicator_history.data_frame
        signal = indicator_history_df["signal"]

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