Trend Intensity Index

Install and import#

npm install fintech-algorithms

import { trendIntensityIndex } from "fintech-algorithms/technical-indicators/trend-systems/trend-intensity-index";

Signature#

trendIntensityIndex(input)

Splits each close into the part above and the part below a simple moving average, sums each part over a second window, and reports the upside sum as a percentage of the two sums combined.

Parameters#

Returns#

TopicResult

series and latest carry a single value key, a percentage between 0 and 100. A bar is null when both deviation sums are zero, which happens only when every close in the window sits exactly on its moving average. The two windows stack, which is what makes the warm-up longer than callers expect.

Warm-up#

The first period + intensity_period - 2 bars (26 by default) positions are null. The moving average needs period bars, and the deviation sum then needs intensity_period non-null deviations on top of it. With both at the default 14 the first value lands at index 26, so ready_at is 26.

Errors#

• When parameters.period or parameters.intensity_period is present but is not an integer of at least 2 — throws Error
• When bars is empty, or a bar has a non-finite price, a negative volume, a timestamp not greater than the previous one, or a high below its open, low, or close — throws Error

Complexity: time O(n * period), space O(n).

Worked example#

executed Captured by running this function on the input its own test provides. Real output of real code — but not asserted against a published figure.

Input#

{
  "bars": [
    {
      "timestamp": "2024-01-02",
      "basis": "synthetic-unadjusted",
      "open": 100,
      "high": 101.45,
      "low": 98.695,
      "close": 100,
      "volume": 750000,
      "benchmark": 200
    },
    {
      "timestamp": "2024-01-03",
      "basis": "synthetic-unadjusted",
      "open": 101.49111452,
      "high": 103.38381693,
      "low": 100.05480022,
      "close": 101.78791214,
      "volume": 795117,
      "benchmark": 200.56326135
    },
    {
      "timestamp": "2024-01-04",
      "basis": "synthetic-unadjusted",
      "open": 102.45519048,
      "high": 104.6701838,
      "low": 100.91147007,
      "close": 102.9549389,
      "volume": 840234,
      "benchmark": 201.11020913
    }
  ],
  "parameters": {}
}

Call#

trendIntensityIndex(input)

Returns#

object with 9 fields: topic_id, title, state, ready, ready_at, series, latest, parameters, …

{
  "topic_id": "D07-F02-A12",
  "title": "Trend Intensity Index",
  "state": "calculated",
  "ready": true,
  "ready_at": 26,
  "series": {
    "value": [null, null, null, null, null, null]
  },
  "latest": {
    "value": 57.21213322600646
  },
  "parameters": {},
  "diagnostics": {
    "causal": true,
    "input_count": 96
  }
}

Diagrams#

Calculation flow#

flowchart LR
    A["ordered OHLC or close observations with explicit window, s"] --> B["Validate order, basis, and finite values"]
    B --> C["Apply the selected Trend Intensity Index convention"]
    C --> D["Emit value, readiness, and diagnostics"]
    D --> E["Interpret descriptively; test outcomes separately"]
    B -->|invalid or insufficient| X["Withhold output with a reason"]

stateDiagram-v2
    [*] --> Waiting
    Waiting --> Ready: enough valid causal observations
    Waiting --> Rejected: malformed or unsupported input
    Ready --> Calculated: selected formula applied
    Calculated --> Interpreted: diagnostic and limitation retained
    Interpreted --> Ready: next observation arrives
    Rejected --> Waiting: corrected input and deterministic reset

How it works#

This page states the contract — how to call it correctly. The article explains the concept: why it works, and where it breaks.

Read the article →

References#

• TA-Lib function groups — see linked primary or authoritative record
• TA-Lib C/C++ API — see linked primary or authoritative record
• TA-Lib maintained source — see linked primary or authoritative record
• Evidence decision
• Level 1 evidence map

The rest of the Trend Systems family#

• MACDMoving average convergence/divergence: the gap between a fast and a slow EMA, its own EMA as a signal line, and the difference …
• Percentage Price Oscillator (PPO)MACD expressed as a percentage of the slow EMA rather than in price units, which makes readings comparable across instruments a…
• Aroon Up, Down, and OscillatorMeasures how recently the highest high and lowest low occurred within the lookback, expressed as 0–100.
• Directional MovementThe components beneath ADX: directional movement in each direction, Wilder-smoothed, divided by the average true range to give …
• Average Directional Index (ADX)Average directional index: the smoothed magnitude of the gap between +DI and −DI.
• Ichimoku CloudThe five Ichimoku lines.
• Parabolic SARStop-and-reverse: a trailing stop that accelerates toward price while a trend persists and flips side when price crosses it.
• SupertrendAn ATR-scaled band around the median price that ratchets in the direction of the trend and only flips when close crosses it.
• Average Directional Index Rating (ADXR)Runs the Wilder directional-movement system over the bars and returns the smoothed plus_di, minus_di and adx lines togeth…
• Vortex Indicator (+VI/−VI)Sums the upward and downward vortex movements over a rolling window and divides each by the summed true range, giving the paire…
• Choppiness IndexCompares the summed true range over a window against the window's own high-to-low span, on a base-10 log scale normalised by th…
• QStickAverages the candle body, close minus open, over a rolling window, so a positive reading means the window closed above its open…
• Mass IndexTakes the ratio of a 9-period EMA of the high-low range to the 9-period EMA of that EMA, then sums the ratio over a longer wind…
• Vertical Horizontal FilterDivides the highest-to-lowest close span over a window by the sum of the absolute bar-to-bar close changes in that same window,…
• Random Walk Index (High/Low)Scores how far price has travelled against what a random walk would explain, by taking the largest displacement-over-expected-r…
• Trend Trigger FactorCompares the current window's high and low against the immediately prior window's, and reports the buy-minus-sell power as a pe…
• Directional Trend IndexWilder-smooths the net of the upward high moves against the downward low moves, and divides it by the smoothed total of both, g…
• Trend Strength IndexMeasures the absolute gap between a fast and a slow EMA of the close in units of average true range, so the spread is comparabl…