Laguerre RSI Pass Node

Laguerre RSI — Series Input

MomentumOscillatorPass

Overview

The Laguerre RSI Pass Node computes the Laguerre RSI on a series input. It applies 4-pole Laguerre filtering to derive an RSI-like oscillator with significantly less lag than standard RSI for equivalent smoothness.

Developed by John Ehlers, the Laguerre RSI uses the same four-pole recursive structure as the Laguerre Filter but normalizes the gain and loss components in the same way as RSI — producing a bounded [0, 1] oscillator. A gamma of 0.5 is the classic Ehlers recommendation, balancing responsiveness and smoothness.

Formula

L0[i] = (1 − gamma) × price + gamma × L0[i−1]
L1[i] = −gamma × L0 + L0[i−1] + gamma × L1[i−1]
L2[i] = −gamma × L1 + L1[i−1] + gamma × L2[i−1]
L3[i] = −gamma × L2 + L2[i−1] + gamma × L3[i−1]
cu = sum of positive differences across L0–L3
cd = sum of negative differences across L0–L3
LaguerreRSI = cu / (cu + cd) → range [0, 1]
No fixed warm-up — recursive from bar 0.

Parameters

ParameterDefaultDescription
gamma0.5Damping coefficient (0–1). Higher = smoother, more lag; lower = more reactive

Inputs & Outputs

SlotDirectionTypeDescription
inputInput{ values, timestamps }Price or any numeric series
valuesOutputnumber[]Laguerre RSI values in [0, 1]; valid from bar 0
timestampsOutputnumber[]Unix timestamps aligned to input

Use Cases

Fast Overbought / Oversold Detection

Use thresholds of 0.8/0.2 (or 0.7/0.3) for overbought/oversold signals. Laguerre RSI reaches extremes faster than standard RSI, making it effective on shorter timeframes.

Scalping on Short Timeframes

On 1-minute or 5-minute bars, Laguerre RSI with gamma=0.3–0.4 is highly responsive to micro-cycle reversals that standard 14-period RSI misses entirely.

Ehlers-Based Systems

Combine with the Laguerre Filter at the same gamma — use the filter for trend direction and the Laguerre RSI for timing entries within that trend.

Tips & Best Practices

Output Scale

Laguerre RSI outputs [0, 1] — not [0, 100] like standard RSI. Apply threshold comparisons accordingly: 0.8 for overbought, 0.2 for oversold (equivalent to RSI 80/20).

Gamma vs Period Equivalence

A rough equivalence: gamma=0.5 corresponds to roughly an 8-period RSI in smoothness, while gamma=0.8 is closer to a 20-period RSI. Adjust based on desired responsiveness.

No Warm-Up Advantage

Like all Laguerre-based indicators, this produces valid output from bar 0 — eliminating the costly warm-up period required by standard RSI or EMA-based oscillators.

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