TdClop

Tom DeMark's TD Clop — a two-bar open/close reversal: the bar opens beyond the whole prior body and closes back beyond it.

Quick reference

Field	Value
Family	DeMark
Input type	Candle (open / close)
Output type	f64 (signed signal)
Output range	{−1, 0, +1}
Default parameters	None (parameter-free)
Warmup period	2
Interpretation	+1 open-gap-down reversal up; −1 open-gap-up reversal down.

Formula

Buy (+1):  open < open[-1] AND open < close[-1]  AND  close > open[-1] AND close > close[-1]
Sell (−1): open > open[-1] AND open > close[-1]  AND  close < open[-1] AND close < close[-1]
otherwise 0

"Clop" = CLose/OPen. A bar that opens below both the prior open and close, then closes above both, has fully reversed an opening gap — a strong bullish turn. The sell pattern mirrors it. Source: crates/wickra-core/src/indicators/td_clop.rs.

Parameters

Name	Type	Default	Valid range	Source	Description
—	—	—	—	None.	TD Clop is parameter-free; TdClop::new() is infallible.

Signed ±1 encoding

+1.0 bullish reversal, −1.0 bearish reversal, 0.0 no pattern (warmup emits None).

Inputs / Outputs

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

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

A Candle in, an Option<f64> out. Python update(candle) / batch(open, high, low, close) → 1-D ndarray; Node update(open, high, low, close) / batch(...).

Warmup

warmup_period() == 2. The first candle seeds the prior bar (first_bar_seeds_without_signal pins this).

Edge cases

• Bullish buy. Open below the prior body, close above it → +1 (bullish_clop_buy pins this).
• Bearish sell. The mirror → −1 (bearish_clop_sell pins this).
• No pattern → 0. Otherwise 0.0 (no_pattern_is_zero pins this).
• Finiteness. Candle::new rejects non-finite fields, so no in-method guard is needed.
• Reset. td.reset() clears the prior bar and the last value (reset_clears_state).

Examples

Rust

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

fn main() -> Result<(), Box<dyn std::error::Error>> {
    let mut td = TdClop::new();
    td.update(Candle::new(10.0, 12.0, 9.0, 11.0, 0.0, 0)?);     // prev body [10,11]
    let sig = td.update(Candle::new(9.0, 13.0, 8.0, 12.0, 0.0, 0)?);
    println!("{:?}", sig); // Some(1.0)
    Ok(())
}

Output:

Some(1.0)

Python

import numpy as np
import wickra as ta

td = ta.TdClop()
o = np.array([10, 9]); h = np.array([12, 13]); l = np.array([9, 8]); c = np.array([11, 12])
print(td.batch(o, h, l, c))  # [nan, 1.0]

Node

const ta = require('wickra');
const td = new ta.TdClop();
td.update(10, 12, 9, 11);
console.log(td.update(9, 13, 8, 12)); // 1

Streaming

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

let mut td = TdClop::new();
let feed: Vec<Candle> = Vec::new(); // your live stream
for candle in feed {
    if let Some(s) = td.update(candle) { if s != 0.0 { /* reversal */ } }
}

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

Interpretation

1. Gap-and-reverse. TD Clop catches opening drives that fail and reverse — a high-conviction one-bar turn.
2. Body engulfment. Because it uses open/close (not high/low), it keys on the body, akin to an Engulfing with DeMark's strict both-sides rule.
3. At levels. Strongest at support/resistance or the end of a Setup count.

Common pitfalls

• Body-only. Wicks are ignored; a long-wick bar can still qualify on its body.
• Strictness. All four inequalities must hold; near-misses do not signal.
• Variant naming. TD Clop is closely related to TD Clopwin (inside-body) — do not confuse the two.

References

Perl, J. (2008), DeMark Indicators, Bloomberg Press.

See also

• Indicator-TdClopwin — the inside-body counterpart.
• Indicator-Engulfing — classic body engulfing.
• Indicator-TdCamouflage — hidden-strength reversal.
• Indicators-Overview — the full taxonomy.