Relative Strength Index (RSI)

Created by J. Welles Wilder, the Relative Strength Index is an oscillator that measures strength of the winning/losing streak over N lookback periods on a scale of 0 to 100, to depict overbought and oversold conditions. [Discuss] 💬

// C# usage syntax
IReadOnlyList<RsiResult> results =
  bars.ToRsi(lookbackPeriods);

Parameters

param	type	description
lookbackPeriods	int	Number of periods (N) in the lookback period. Must be greater than 0. Default is 14.

Historical price bars requirements

You must have at least N+100 periods of bars to cover the warmup and convergence periods. Since this uses a smoothing technique, we recommend you use at least 10×N 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<RsiResult>

• 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-1 periods will have null values since there's not enough data to calculate.

🚩 ⚞ Convergence warning

The first 10×N periods will have decreasing magnitude, convergence-related precision errors that can be as high as ~5% deviation in indicator values for earlier periods.

RsiResult

property	type	description
Timestamp	DateTime	Date from evaluated TBar
Rsi	double	Relative Strength Index

Utilities

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

See Utilities and helpers for more information.

Chaining

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

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

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

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

See Chaining indicators for more.

Streaming

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

RsiList rsiList = new(lookbackPeriods);

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

// based on `ICollection<RsiResult>`
IReadOnlyList<RsiResult> results = rsiList;

Subscribe to a BarHub for advanced streaming scenarios:

BarHub barHub = new();
RsiHub observer = barHub.ToRsiHub(lookbackPeriods);

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

IReadOnlyList<RsiResult> results = observer.Results;

See Buffer lists and Stream hubs for full usage guides.