DumplingTop

The bearish mirror of the Frying Pan Bottom — a gently rounded top (dome) confirmed by a close back below where the dome began.

Quick reference

Field	Value
Family	Candlestick Patterns
Input type	Candle (close)
Output type	f64
Output range	{−1, 0}
Default parameters	(period = 9) (Python)
Warmup period	period
Interpretation	−1 rounded top breakdown.

Formula

over the last `period` closes:
  the maximum close sits in the middle (index in [period/4, 3·period/4))  -> a dome
  latest close < first close  AND  latest close < maximum close            -> breakdown
signal = −1 when both hold, else 0

The dumpling top is a distribution dome: buying fades, price rounds over, and rolls down through the level it rose from. Detection needs a central high (symmetric dome, not a one-sided spike) and a close below the window's opening level. Source: crates/wickra-core/src/indicators/dumpling_top.rs.

Parameters

Name	Type	Default	Valid range	Source	Description
period	usize	9 (Python)	>= 5	dumpling_top.rs:48	Window length of the rounded top. < 5 errors with Error::InvalidPeriod.

The period getter returns the window; value returns the current output if ready.

Inputs / Outputs

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

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

A Candle in, an Option<f64> out (−1/0). Python update(candle) / batch(close); Node update(close) / batch(close[]).

Warmup

warmup_period() == period. The window must fill first (first_emission_at_warmup_period pins this).

Edge cases

• Rounded top → −1. A dome then breakdown signals (rounded_top_then_breakdown_signals pins this).
• One-sided rise → 0. A straight advance is not a dome (one_sided_rise_is_zero pins this).
• No breakdown → 0. A dome that never loses the rim does not signal (no_breakdown_is_zero pins this).
• Finiteness. Candle::new rejects non-finite fields, so no in-method guard is needed.
• Reset. d.reset() clears the close window and the last value (reset_clears_state).

Examples

Rust

use wickra::{BatchExt, Candle, Indicator, DumplingTop};

fn main() -> Result<(), Box<dyn std::error::Error>> {
    let mut d = DumplingTop::new(9)?;
    let closes = [100.0, 102.0, 104.0, 105.0, 104.0, 102.0, 99.0, 97.0, 95.0];
    let candles: Vec<Candle> = closes.iter().map(|&x| Candle::new(x, x+0.5, x-0.5, x, 1_000.0, 0).unwrap()).collect();
    println!("{:?}", d.batch(&candles).last().unwrap()); // Some(-1.0)
    Ok(())
}

Output:

Some(-1.0)

Python

import numpy as np
import wickra as ta

d = ta.DumplingTop(9)
close = np.array([100, 102, 104, 105, 104, 102, 99, 97, 95], float)
print(d.batch(close)[-1])  # -1.0

Node

const ta = require('wickra');
const d = new ta.DumplingTop(9);
console.log(d.batch([100, 102, 104, 105, 104, 102, 99, 97, 95]).at(-1)); // -1

Streaming

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

let mut d = DumplingTop::new(9).unwrap();
let feed: Vec<Candle> = Vec::new(); // your live stream
for candle in feed {
    if d.update(candle) == Some(-1.0) { println!("dumpling top"); }
}

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

Interpretation

1. Distribution dome. The rounded top signals supply overwhelming demand; the breakdown is the exit/short trigger.
2. Volume. A classic dumpling top often shows a volume spike at the breakdown.
3. Target. Project the dome's height below the breakdown for a measured move.

Common pitfalls

• Window sizing. Too short calls every pullback a top; too long misses compact domes.
• Close-only. Intrabar spikes are ignored.
• Bearish only. For the rounded base see FryPanBottom.

References

A Japanese candlestick rounded-top pattern; see Nison, S. (1994), Beyond Candlesticks, and Bulkowski, T. N. (2005), Encyclopedia of Chart Patterns.

See also

• Indicator-FryPanBottom — the rounded-bottom mirror.
• Indicator-TowerTopBottom — abrupt reversal.
• Indicator-DoubleTopBottom — double-extreme reversal.
• Indicators-Overview — the full taxonomy.