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Donchian Channels

Classic breakout volatility trend classic support-resistance

Donchian Channels are volatility indicators formed by taking the highest high and the lowest low of the last N periods.

Visual Example

Donchian Channels — annotated preview mapping to core implementation

Synthetic ideal per library logic. Generated 2026-07-01 IST via docs/generate_all_previews.py (reproducible; maps to core Next<T> implementation).

Description

Donchian Channels are volatility indicators formed by taking the highest high and the lowest low of the last N periods.

Use for breakout trading systems: a close above the N-period high signals a long entry; below the N-period low signals a short entry. The Turtle Traders famously used 20 and 55-day Donchian channels.

Native Rust implementation with gold-standard or TA-Lib parity tests where applicable.

Developed by Richard Donchian in the 1970s, Donchian Channels plot the highest high and lowest low over N bars. They define the current trading range and signal breakouts when price escapes the channel. The Turtle Trading system of Richard Dennis built its entire entry and exit logic on 20 and 55-day Donchian channels. — TurtleTrader.com

Typical applications:

  • Size stops and position risk from band width or ATR expansion
  • Detect squeeze conditions (narrow bands) before breakout systems
  • Warm-up: first 20 bars build rolling volatility state
  • Combine with trend direction (SuperTrend, MACD) for breakout bias

QuantWave implements this via the universal Next<T> trait — bit-identical across Rust streaming, Python streaming, and Polars .ta() batch plugins.

Formula / Specification

Implementation (quantwave-core/src/indicators/donchian.rs):

\[ UC = \max(H_{t-n \dots t}) \\ LC = \min(L_{t-n \dots t}) \]

Gold-standard parity vectors: quantwave-core/tests/gold_standard/donchian.json.

Parameters

Parameter Default Description
period 20 Channel period

Usage Examples

Streaming (Rust)

use quantwave_core::indicators::DONCHIAN;
use quantwave_core::traits::Next;

let mut ind = DONCHIAN::new(20);
for price in &prices {
    let value = ind.next(price);
}

Streaming (Python)

from quantwave import DONCHIAN

ind = DONCHIAN(20)
for price in prices:
    value = ind.next(price)

Polars Batch (Python)

import polars as pl
import quantwave as qw

def apply_donchian_channels(series: pl.Series) -> pl.Series:
    ind = qw.DONCHIAN(20)
    return pl.Series([ind.next(float(v)) for v in series.to_list()])

df = (
    pl.read_csv('ohlcv.csv')
    .lazy()
    .with_columns(
        pl.col("close").map_batches(apply_donchian_channels, return_dtype=pl.Float64).alias("donchian_channels")
    )
    .collect()
)

All surfaces are bit-identical via the single Next<T> implementation and proptests.

Edge Cases & Limitations

  • Warm-up: first 20 bars may return NaN or partial state per implementation.
  • Parameter sensitivity: smaller periods increase noise; larger periods increase lag.
  • Sudden gaps or bad ticks can distort rolling windows — consider pre-filtering.
  • Single-series indicators ignore volume unless otherwise documented.
  • Validated via proptests against gold-standard vectors where available.
  • No look-ahead bias; streaming and Polars batch paths are bit-identical.

Boundary Behavior

Condition Behavior
Warm-up Leading bars return NaN until warmup_bars is satisfied.
period > len When period exceeds series length, output is all NaN.
NaN inputs NaN in input propagates to output (NaN out).
Invalid params Non-positive period or missing required params raise ValueError.
Empty data Empty input returns an empty result series.

Sources & References

Primary Source: https://www.investopedia.com/terms/d/donchianchannels.asp

Implementation: quantwave-core/src/indicators/donchian.rs (DONCHIAN / DONCHIAN_METADATA). Parity: quantwave-core/tests/gold_standard/donchian.json

Provenance: Standards bulk upgrade 2026-07-01 IST — see docs/DOCUMENTATION_STANDARDS.md.