TowerTopBottom

A tall directional bar, a small pause bar, then a tall opposite bar — two "towers" flanking a low wall, a compact reversal.

Quick reference

Field	Value
Family	Candlestick Patterns
Input type	Candle (open / high / low / close)
Output type	f64 (signed signal)
Output range	{−1, 0, +1}
Default parameters	None (body thresholds fixed)
Warmup period	3
Interpretation	+1 tower bottom; −1 tower top.

Formula

tall  bar: |close − open| >= 0.5 · range
small bar: |close − open| <= 0.3 · range
Tower Bottom (+1): tall bearish , small , tall bullish
Tower Top    (−1): tall bullish , small , tall bearish
otherwise 0

A strong move, a pause, then a strong move the other way marks a reversal. This is the three-bar form of the classic multi-bar Tower pattern. Source: crates/wickra-core/src/indicators/tower_top_bottom.rs.

Parameters

Name	Type	Default	Valid range	Source	Description
—	—	—	—	None.	Tower is parameter-free; the tall (0.5) / small (0.3) body-fraction thresholds are fixed.

Signed ±1 encoding

+1.0 tower bottom (bullish), −1.0 tower top (bearish), 0.0 no pattern (warmup emits None).

Inputs / Outputs

From crates/wickra-core/src/indicators/tower_top_bottom.rs:

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

A Candle in, an Option<f64> out. Python update(candle) / batch(open, high, low, close); Node update(open, high, low, close) / batch(...).

Warmup

warmup_period() == 3. Two candles seed the buffer (first_two_bars_seed_without_signal pins this).

Edge cases

• Tower top. Tall bullish, pause, tall bearish → −1 (tower_top pins this).
• Tower bottom. The mirror → +1 (tower_bottom pins this).
• Same direction → 0. Both outer bars same way → no tower (same_direction_is_zero pins this).
• No pause → 0. A tall middle bar breaks it (no_pause_is_zero pins this).
• Finiteness. Candle::new rejects non-finite fields, so no in-method guard is needed.
• Reset. t.reset() clears the two prior candles and the last value (reset_clears_state).

Examples

Rust

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

fn main() -> Result<(), Box<dyn std::error::Error>> {
    let mut t = TowerTopBottom::new();
    t.update(Candle::new(100.0, 110.1, 99.9, 110.0, 0.0, 0)?); // tall bullish
    t.update(Candle::new(110.0, 112.0, 108.0, 110.1, 0.0, 0)?); // small pause
    let sig = t.update(Candle::new(110.0, 110.1, 99.9, 100.0, 0.0, 0)?); // tall bearish
    println!("{:?}", sig); // Some(-1.0)
    Ok(())
}

Output:

Some(-1.0)

Python

import numpy as np
import wickra as ta

t = ta.TowerTopBottom()
o = np.array([100, 110, 110]); h = np.array([110.1, 112, 110.1]); l = np.array([99.9, 108, 99.9]); c = np.array([110, 110.1, 100])
print(t.batch(o, h, l, c))  # [nan, nan, -1.0]

Node

const ta = require('wickra');
const t = new ta.TowerTopBottom();
t.update(100, 110.1, 99.9, 110); t.update(110, 112, 108, 110.1);
console.log(t.update(110, 110.1, 99.9, 100)); // -1

Streaming

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

let mut t = TowerTopBottom::new();
let feed: Vec<Candle> = Vec::new(); // your live stream
for candle in feed {
    match t.update(candle) {
        Some(1.0)  => println!("tower bottom"),
        Some(-1.0) => println!("tower top"),
        _ => {}
    }
}

Streaming update and batch are equivalent tick-for-tick (batch_equals_streaming pins this).

Interpretation

1. Sharp reversal. Towers mark abrupt turns — the pause is brief and the opposite thrust decisive.
2. Context. Strongest at the end of a clear trend into a level.
3. Confirm. A follow-through bar after the second tower adds conviction.

Common pitfalls

• Compact form. Classic Towers can span more bars; this three-bar version is a practical proxy.
• Threshold reliance. The tall/small classification is fixed; very-low-range bars (no range) never qualify.
• Trend required. Mid-range towers are noise.

References

Nison, S. (1994), Beyond Candlesticks.

See also

• Indicator-MorningEveningStar — star reversal.
• Indicator-Engulfing — two-bar reversal.
• Indicator-DumplingTop — rounded-top reversal.
• Indicators-Overview — the full taxonomy.