Volume Rate of Change
Install and import#
npm install fintech-algorithmsimport { volumeRateOfChange } from "fintech-algorithms/technical-indicators/volume-indicators/volume-rate-of-change";Signature#
volumeRateOfChange(input)Measures the percentage change in volume against the bar period positions earlier.
Parameters#
| Name | Type | Notes |
|---|---|---|
input | TopicInput | bars needs timestamp and volume. From parameters this topic reads period (default 14, an integer of at least 2). |
Returns#
TopicResult
series holds a single value, 100 times volume / lagged volume - 1, and latest its last element. A bar whose lagged volume is 0 yields null. The warm-up is the lag itself.
Warm-up#
The first `period` bars (14 with the default) positions are null. ready_at is 14 on default parameters, one more than the moving-average topics in this family because the comparison is a lag rather than a window.
Errors#
- When
periodis not an integer of at least 2 — throws Error - When a bar carries a negative
volume— throws Error - When a
volumeis not a finite number — throws Error
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#
{
"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#
volumeRateOfChange(input)Returns#
object with 9 fields: topic_id, title, state, ready, ready_at, series, latest, parameters, …
{
"topic_id": "D07-F05-A16",
"title": "Volume Rate of Change",
"state": "calculated",
"ready": true,
"ready_at": 14,
"series": {
"value": [null, null, null, null, null, null]
},
"latest": {
"value": 25.301129103211338
},
"parameters": {},
"diagnostics": {
"causal": true,
"input_count": 96
}
}Diagrams#
Calculation flow#
Volume Rate of Change calculation flow
flowchart LR
A["basis-consistent OHLCV observations with venue/session cov"] --> B["Validate order, basis, and finite values"]
B --> C["Apply the selected Volume Rate of Change 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"]
Volume Rate of Change readiness and evidence states
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.
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