QuanTAlib/lib/trends/super/Super.md

SuperTrend: SuperTrend Indicator

What It Does

The SuperTrend indicator is a popular trend-following tool that combines price action with volatility. It plots a line above or below the price to indicate the current trend direction and potential stop-loss levels. When the price is above the SuperTrend line, the trend is bullish (green). When the price is below the line, the trend is bearish (red).

Historical Context

Created by Olivier Seban, the SuperTrend indicator was designed to be a simple, visual system for identifying trends and managing trailing stops. It gained massive popularity in retail trading communities due to its clear "buy/sell" visual nature and its ability to filter out minor fluctuations while keeping traders in major moves.

How It Works

The Core Idea

SuperTrend uses the Average True Range (ATR) to measure market volatility. It then calculates a "Basic Upper Band" and "Basic Lower Band" based on the average price (HL2) plus/minus a multiple of the ATR.

The "SuperTrend" line itself is a stateful logic that switches between the Upper and Lower bands based on price action:

• If price closes above the Upper Band, the trend flips to Bullish, and the line becomes the Lower Band.
• If price closes below the Lower Band, the trend flips to Bearish, and the line becomes the Upper Band.

Mathematical Foundation

1. ATR Calculation: Calculate the Average True Range for period N.
2. Basic Bands: Upper_{basic} = \frac{High + Low}{2} + (Multiplier \times ATR) Lower_{basic} = \frac{High + Low}{2} - (Multiplier \times ATR)
3. Final Bands (Trailing Logic):
   • Upper_{final}: If current Upper_{basic} < prev Upper_{final} or prev Close > prev Upper_{final}, then Upper_{basic}, else prev Upper_{final}.
   • Lower_{final}: If current Lower_{basic} > prev Lower_{final} or prev Close < prev Lower_{final}, then Lower_{basic}, else prev Lower_{final}.
4. SuperTrend Logic:
   • If Trend is Bullish: SuperTrend = Lower_{final}
   • If Trend is Bearish: SuperTrend = Upper_{final}

Implementation Details

Our implementation maintains the state of the trend and the trailing bands.

• Complexity: O(1) per update.
• State: Requires tracking the previous trend direction, previous final bands, and previous close.

Configuration

Parameter	Default	Purpose	Adjustment Guidelines
Period	10	ATR Lookback	10 is standard. Shorter = more volatile ATR.
Multiplier	3.0	Band width	3.0 is standard. Lower (e.g., 2.0) = tighter stops, more signals. Higher (e.g., 4.0) = wider stops, fewer signals.

Performance Profile

Operation	Complexity	Description
Streaming update	O(1)	ATR update + logic checks
Bar correction	O(1)	Efficient state rollback
Batch processing	O(N)	Single pass through data
Memory footprint	O(period)	RingBuffer for ATR calculation

Interpretation

Trading Signals

Trend Reversal

• Buy Signal: Price closes above the SuperTrend line (Trend flips from Bearish to Bullish).
• Sell Signal: Price closes below the SuperTrend line (Trend flips from Bullish to Bearish).

Trailing Stop

• The SuperTrend line itself serves as an excellent trailing stop-loss level. In an uptrend, place stops just below the green line. In a downtrend, place stops just above the red line.

When It Works Best

• Trending Markets: SuperTrend excels at capturing large moves and keeping you in the trade until the trend actually reverses.

When It Struggles

• Sideways Markets: In choppy, range-bound markets, price will frequently cross the line, causing "whipsaws" (rapid buy/sell signals that result in losses).

Architecture Notes

This implementation makes specific trade-offs:

Choice: ATR Smoothing

• Implementation: Uses RMA (Wilder's Smoothing) for ATR calculation.
• Rationale: Standard definition of ATR uses RMA. Using SMA or EMA would deviate from the standard SuperTrend formula found on most platforms.

References

• Seban, Olivier. "Tout le monde mérite d'être riche" (Everyone Deserves to Be Rich).

C# Usage

Streaming Updates (Single Instance)

using QuanTAlib;

var super = new SuperTrend(period: 10, multiplier: 3.0);

// Process each new bar
TBar bar = new TBar(time, open, high, low, close, volume);
TValue result = super.Update(bar);

Console.WriteLine($"SuperTrend: {result.Value:F2}");
Console.WriteLine($"Trend: {(result.IsBullish ? "Bullish" : "Bearish")}");

// Check if buffer is full
if (super.IsHot)
{
    // Indicator is fully initialized
}

Batch Processing (Historical Data)

// TBarSeries API
TBarSeries bars = ...;
TSeries superValues = SuperTrend.Batch(bars, period: 10, multiplier: 3.0);

Bar Correction (isNew Parameter)

var super = new SuperTrend(10, 3.0);

// New bar
super.Update(bar, isNew: true);

// Intra-bar update
super.Update(updatedBar, isNew: false); // Replaces last calculation