Gap Momentum
Accumulates positive and negative opening gaps to derive a cumulative gap ratio, smoothed by a signal line.
Visual Example

Synthetic ideal per library logic. Generated 2026-07-01 IST via docs/generate_all_previews.py (reproducible; maps to core Next<T> implementation).
Description
Accumulates positive and negative opening gaps to derive a cumulative gap ratio, smoothed by a signal line.
Used to identify momentum shifts based on price gaps. Buy when the signal line is rising and sell when it is falling.
Native Rust implementation with gold-standard or TA-Lib parity tests where applicable.
Perry J. Kaufman introduced Gap Momentum as a way to quantify price gaps relative to their cumulative volatility, similar to an On-Balance Volume (OBV) logic applied to opening gaps. It helps traders identify if gap-driven momentum is increasing or decreasing by comparing the sum of upward gaps against downward gaps over a rolling window. — Perry Kaufman, S&C 2024
Typical applications:
- Fade extremes in ranges; trade with trend on recoveries from oversold/overbought
- Use divergences as early warning — confirm with structure or volume
- Parameter default
40— shorten for sensitivity, lengthen for stability - Drop into
build_feature_matrix()for ML research
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/gap_momentum.rs):
[ Gap = Open_t - Close_{t-1} ] [ UpGaps = \sum_{i=0}^{Period-1} \max(0, Gap_{t-i}) ] [ DnGaps = \sum_{i=0}^{Period-1} \max(0, -Gap_{t-i}) ] [ GapRatio = \begin{cases} 1 & \text{if } DnGaps = 0 \ 100 \times \frac{UpGaps}{DnGaps} & \text{otherwise} \end{cases} ] [ Signal = SMA(GapRatio, SignalPeriod) ]
Gold-standard parity vectors: quantwave-core/tests/gold_standard/gap_momentum.json.
Parameters
| Parameter | Default | Description |
|---|---|---|
period |
40 | Rolling window for gap accumulation |
signal_period |
20 | Smoothing period for the gap ratio |
Usage Examples
Streaming (Rust)
use quantwave_core::indicators::GAP_MOMENTUM;
use quantwave_core::traits::Next;
let mut ind = GAP_MOMENTUM::new(40);
for price in &prices {
let value = ind.next(price);
}
Streaming (Python)
from quantwave import GAP_MOMENTUM
ind = GAP_MOMENTUM(40)
for price in prices:
value = ind.next(price)
Polars Batch (Python)
import polars as pl
import quantwave as qw
def apply_gap_momentum(series: pl.Series) -> pl.Series:
ind = qw.GAP_MOMENTUM(40)
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_gap_momentum, return_dtype=pl.Float64).alias("gap_momentum")
)
.collect()
)
All surfaces are bit-identical via the single Next<T> implementation and proptests.
Edge Cases & Limitations
- Warm-up: first
40bars 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. |
Related Indicators & See Also
Sources & References
Primary Source: https://github.com/lavs9/quantwave/blob/main/references/traderstipsreference/TRADERS%E2%80%99%20TIPS%20-%20JANUARY%202024.html
Implementation: quantwave-core/src/indicators/gap_momentum.rs (GAP_MOMENTUM / GAP_MOMENTUM_METADATA).
Parity: quantwave-core/tests/gold_standard/gap_momentum.json
Provenance: Standards bulk upgrade 2026-07-01 IST — see docs/DOCUMENTATION_STANDARDS.md.