True Strength Index (TSI)

Created by William Blau, the True Strength Index is a momentum oscillator that uses a series of exponential moving averages to depicts trends in price changes. [Discuss] 💬

// C# usage syntax
IReadOnlyList<TsiResult> results =
  bars.ToTsi(lookbackPeriods, smoothPeriods, signalPeriods);

Parameters

param	type	description
lookbackPeriods	int	Number of periods (N) for the first EMA. Must be greater than 0. Default is 25.
smoothPeriods	int	Number of periods (M) for the second smoothing. Must be greater than 0. Default is 13.
signalPeriods	int	Number of periods (S) in the TSI moving average. Must be greater than or equal to 0. Default is 7.

Historical price bars requirements

You must have at least N+M+100 periods of bars to cover the warmup and convergence periods. Since this uses a two-stage EMA smoothing technique, we recommend you use at least N+M+250 data points prior to the intended usage date for better precision.

bars is a collection of generic TBar historical price bars. It should have a consistent frequency (day, hour, minute, etc). See the Guide for more information.

Response

IReadOnlyList<TsiResult>

• This method returns a time series of all available indicator values for the bars provided.
• It always returns the same number of elements as there are in the historical price bars.
• It does not return a single incremental indicator value.
• The first N+M-1 periods will have null values since there's not enough data to calculate.
• Signal will be null for all periods if signalPeriods=0.

🚩 ⚞ Convergence warning

The first N+M+250 periods will have decreasing magnitude, convergence-related precision errors that can be as high as ~5% deviation in indicator values for earlier periods.

TsiResult

property	type	description
Timestamp	DateTime	Date from evaluated TBar
Tsi	double	True Strength Index
Signal	double	Signal line (EMA of TSI)

Utilities

• .Condense()
• .Find(lookupDate)
• .RemoveWarmupPeriods()
• .RemoveWarmupPeriods(removePeriods)

See Utilities and helpers for more information.

Streaming

Use the buffer-style List<T> when you need incremental calculations without a hub:

TsiList tsiList = new(lookbackPeriods, smoothPeriods, signalPeriods);

foreach (IBar bar in bars)  // simulating stream
{
  tsiList.Add(bar);
}

// based on `ICollection<TsiResult>`
IReadOnlyList<TsiResult> results = tsiList;

Subscribe to a BarHub for advanced streaming scenarios:

BarHub barHub = new();
TsiHub observer = barHub.ToTsiHub(lookbackPeriods, smoothPeriods, signalPeriods);

foreach (IBar bar in bars)  // simulating stream
{
  barHub.Add(bar);
}

IReadOnlyList<TsiResult> results = observer.Results;

See Buffer lists and Stream hubs for full usage guides.

Chaining

This indicator may be generated from any chain-enabled indicator or method.

// example
var results = bars
    .Use(CandlePart.HL2)
    .ToTsi(..);

Results can be further processed on Tsi with additional chain-enabled indicators.

// example
var results = bars
    .ToTsi(..)
    .ToSlope(..);

See Chaining indicators for more.