Force Index
Install and import#
npm install fintech-algorithmsimport { forceIndex } from "fintech-algorithms/technical-indicators/volume-indicators/force-index";Signature#
forceIndex(close, volume, p)Price change multiplied by volume, then smoothed. Combines direction, size and participation in one number — a large move on no volume scores low.
Parameters#
| Name | Type | Notes |
|---|---|---|
close | number[] | Per-bar closing prices, chronological. |
volume | number[] | Per-bar traded volume, aligned index-for-index with the price series. |
p | number | EMA span applied to the raw force series. min: 1 · integer: true |
Returns#
Record<string, (number | null)[]> · length same-as-input
Parallel series: change, volume, raw_force, ema_seed and the smoothed force_index.
Warm-up#
The first p positions are null. One bar for the price change, then the EMA seed window.
Errors#
- When p < 1 or is not an integer — throws RangeError
- When the input series are not all the same length — throws RangeError
Complexity: time O(n),
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#
[100.28, 100.686113, 101.200346, 101.789282, 102.408843, 103.010585]Showing 6 of 120 elements.
[990000, 1066468.036, 1130033.236, 1170141.961, 1180511.26, 1160272.794]Showing 6 of 120 elements.
Call#
forceIndex(close, volume, p)Returns#
object with 5 fields: change, volume, raw_force, ema_seed, force_index
{
"change": [
null,
0.40611300000000483,
0.5142329999999902,
0.5889360000000039,
0.6195610000000045,
0.6017420000000016
],
"volume": [990000, 1066468.036, 1130033.236, 1170141.961, 1180511.26, 1160272.794],
"raw_force": [
null,
433106.53350407316,
581100.3810479769,
689138.7259435005,
731398.7367568653,
698184.8716071498
],
"ema_seed": [null, null, null, null, null, null],
"force_index": [null, null, null, null, null, null]
}Other exports#
This module also exports
obv, accumulationDistributionLine, chaikinMoneyFlow, moneyFlowIndex, volumePriceTrend. Every module additionally exports run as an alias of its
primary function, and a meta object carrying its catalog id, domain, family,
shape and article URL.
Diagrams#
Calculation flow#
Calculation flow
flowchart LR
A["Finalized finalized close and nonnegative volume"] --> B["Validate order, alignment, and finite values"]
B --> C["Close change"]
C --> D["Raw price-volume force"]
D --> E["EMA seed / update"]
E --> F{"History and denominator valid?"}
F -- "No · short history" --> G["warming-up + reason"]
F -- "No · no finite scale" --> H["undefined + reason"]
F -- "Yes" --> I["Smoothed Force Index"]
I --> J["ready + aligned component trace"]
Data-basis reconciliation — Force Index
flowchart LR
A["Same instrument and identifier?"] -->|Yes| B["Same venue or consolidated scope?"]
A -->|No| X["Stop: different measurement"]
B -->|Yes| C["Same volume unit and bar interval?"]
B -->|No| X
C -->|Yes| D["Same session and close policy?"]
C -->|No| X
D -->|Yes| E["Same corrections and price-volume adjustment basis?"]
D -->|No| X
E -->|Yes| F["Same Force Index convention, seed, warm-up, and precision?"]
E -->|No| X
F -->|Yes| G["Compare intermediate components"]
F -->|No| Y["Document convention difference"]
G --> H["Compare final output"]
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.
References#
- Elder's Force Index (EFI) — TradingView
- Volume — TradingView
- Consolidated Tape — U.S. Securities and Exchange Commission, Investor.gov
- Closing Price — U.S. Securities and Exchange Commission, Investor.gov
- What is Volume? — CME Group
- Claim-role ledger
- Evidence boundary
- Enhanced claim-to-source map
- Public evidence boundary