RVI

Relative Vigor Index — Donald Dorsey's ratio of intra-bar drive (close − open) to intra-bar range (high − low), averaged over a period-bar window.

Quick reference

Field	Value
Family	Momentum Oscillators
Input type	Candle (uses open, high, low, close)
Output type	f64
Output range	unbounded; for clean OHLC the ratio sits in (−1, 1)
Default parameters	period = 10
Warmup period	period (exact)
Interpretation	Positive on average-bullish windows, negative on average-bearish.

Formula

num_t = close_t − open_t
den_t = high_t  − low_t
RVI_t = SMA(num, period)_t / SMA(den, period)_t

Equivalently — and this is what Wickra computes — RVI is the ratio of the rolling sums (the per-window divisor period cancels). If the denominator sum is non-positive (every bar in the window had zero range), the indicator holds its previous value rather than emit NaN.

This is the Relative Vigor Index (momentum). The similarly-named Relative Volatility Index is a separate indicator — see RVIVolatility.

Parameters

Name	Type	Default	Constraint	Source
period	usize	10	>= 1	Rvi::new (rvi.rs:46)

period == 0 returns [Error::PeriodZero]. Python default comes from #[pyo3(signature = (period=10))]; the Node constructor takes period explicitly. The public class is RVI in both bindings.

Inputs / Outputs

use wickra::{Indicator, Rvi, Candle};
// Rvi: Input = Candle, Output = f64
const _: fn(&mut Rvi, Candle) -> Option<f64> = <Rvi as Indicator>::update;

Uses all four OHLC fields.

• Python. update(candle) returns float | None; batch(open, high, low, close) returns a 1-D float64 np.ndarray with NaN warmup.
• Node. update(open, high, low, close) returns number | null; batch(open, high, low, close) returns an Array<number> with NaN warmup.

Warmup

warmup_period() returns period. The two rolling sums need a full period window, so the first non-None output lands on candle period (index period − 1). Pinned by warmup_emits_first_value_at_period.

Edge cases

• Reference. RVI(2) on (10,11,9,10.5) then (10.5,11.5,10,11): numerator sum 0.5 + 0.5 = 1.0, denominator sum 2.0 + 1.5 = 3.5, so RVI = 1/3.5 ≈ 0.2857 (test reference_value_period_2).
• Pure uptrend. Every bar closes above its open with non-zero range, so RVI > 0 (test pure_uptrend_is_positive).
• Zero-range window. Every bar high == low ⇒ denominator sum 0 ⇒ the indicator holds (test zero_range_window_holds_value).
• Reset. reset() clears the window, both sums and the running value.

Examples

Rust

use wickra::{Candle, Indicator, Rvi};

fn main() -> Result<(), Box<dyn std::error::Error>> {
    // open, high, low, close, volume, ts
    let mut r = Rvi::new(2)?;
    let _ = r.update(Candle::new(10.0, 11.0, 9.0, 10.5, 1.0, 0)?); // None
    let v = r.update(Candle::new(10.5, 11.5, 10.0, 11.0, 1.0, 1)?).unwrap();
    println!("{v:.4}"); // 0.2857
    Ok(())
}

Python

import numpy as np
import wickra as ta

r = ta.RVI(10)
out = r.batch(open_, high, low, close)  # 1-D series, NaN for the first 9 rows

Node

const ta = require('wickra');
const r = new ta.RVI(10);
const v = r.update(10.5, 11.5, 10.0, 11.0); // open, high, low, close

Interpretation

RVI reads the conviction behind a window's bars — how much of each bar's range was converted into a directional close-vs-open move:

1. Sign = average bias. Positive means the average bar in the window closed above its open (bullish vigor); negative the reverse.
2. Signal-line use. Dorsey's full system applies a 4-bar weighted smoothing and a signal line; Wickra publishes the raw ratio so you can smooth it with a Chain or your own Sma/Ema.

Common pitfalls

• Confusing it with the Relative Volatility Index. Different indicator, shared abbreviation — see RVIVolatility.
• Expecting hard ±1 bounds. For clean OHLC the ratio stays in (−1, 1), but gaps between open and prior close can push it outside; it is not clamped.

References

• Donald Dorsey, "The Relative Vigor Index", Technical Analysis of Stocks & Commodities. The 4-bar weighted "vigor" variant is not built in; compose it with Chaining if needed.

See also

• Inertia — a linear-regression smoothing of RVI.
• RVIVolatility — the unrelated volatility RVI.
• Stochastic — another close-position oscillator.