Inverse Sort Index Map
Return each original value’s position in a stable ascending numeric sort, the inverse argsort mapping; ties remain stable.
Description
Return each original value’s position in a stable ascending numeric sort, the inverse argsort mapping; ties remain stable.
An inverse argsort maps each original position to its position after stable sorting.
When to use this tool
Return each original value’s position in a stable ascending numeric sort, the inverse argsort mapping; ties remain stable.
- Prepare the supplied values fields for this operation.
- Compare the complete example with the representation used by your own input before carrying the result into another step.
How to use the tool and how it works
- Enter values. Use the exact text syntax, units and index conventions explained below.
- Run the tool. If input validation fails, correct the supplied fields before interpreting any result.
- Read result.positions. Interpret false, null and empty lists using the distinctions below; they can be valid outputs.
Compute source indexes sorted by ascending value and original-index ties. Return, for each original index, its zero-based location in that sorted sequence.1
| Input field | Meaning and representation | Accepted input |
|---|---|---|
| values | values. | List of finite numbers; at most 128 entries |
| Output field | Interpretation |
|---|---|
| result | Object containing the named outputs below. |
| result.positions | The positions list in the ordering and representation described above. |
{
"input": {
"values": [
30,
10,
10,
20
]
},
"output": {
"result": {
"positions": [
3,
0,
1,
2
]
}
}
}Limitations and assumptions
- These are positions rather than one-based ranks. Equal values occupy distinct positions according to original order.
- All declared input fields are required and unexpected top-level fields are rejected. Numbers must be finite; lists are limited to 128 entries and ordinary text fields to 8,192 UTF-16 code units, with tighter limits where stated.
- JSON text inputs must parse within bounded nesting and size limits. Numeric outputs outside the safe finite range are rejected; large exact integer results use decimal strings. Indexes and half-open spans are zero-based unless a rank is explicitly described as one-based.
Alternative or Complementary methods
Choose the tie policy and whether you need values, original indexes, sorted positions or one-based ranks. Use a complete sort verifier when a local stability or adjacent-comparison check is insufficient.
References
Similar or alternative tools
- Sort Key Tie Stability Audit
Audit only tie-order stability of an explicit numeric sort permutation, independently of whether the keys themselves are sorted.
- Sorted Run Merge Plan
Produce a stable merge provenance plan for sorted numeric runs, breaking equal keys by earlier run index without mutating runs.