Sparse Row Pointer Layout Validator

Description

Validate CSR pointer arity, monotonicity, final entry count and minor bounds; duplicates/unsorted minor indexes remain legal observations.

A sparse matrix can be stored as coordinate triplets or as pointer/index/value arrays. Stored entries are not necessarily distinct numerical nonzeros: duplicates and explicit zeros can matter to representation checks. Row and column coordinates here are zero-based, and omitted entries are handled only as stated for the particular operation.

Validate CSR pointer arity, monotonicity, final entry count and minor bounds; duplicates/unsorted minor indexes remain legal observations.

When to use this tool

Use this tool to validate CSR pointer arity, monotonicity, final entry count and minor bounds; duplicates/unsorted minor indexes remain legal observations.

How to use the tool and how it works

Enter pointers, indexes, values, major, minor using the field definitions below.
Run the operation. Correct input errors before interpreting an output.
Read result.valid, result.entries, result.emptyMajorIndexes. Use the ordering, boundary rules and absence conditions described below.

Require a zero first pointer, nondecreasing pointers, final pointer equal to entry count, aligned values and in-range column indexes. Return valid true and empty row indexes.^[1]

Input field	Meaning and units	Accepted input
pointers	Zero-based cumulative row or column pointers, starting at 0 and ending at entry count.	Dense list of at most 128 finite numbers; integer/shape constraints above also apply.
indexes	Minor-axis integer indexes aligned with values, not source-record positions.	Dense list of at most 128 finite numbers; integer/shape constraints above also apply.
values	Finite stored entry values aligned with indexes.	Dense list of at most 128 finite numbers; integer/shape constraints above also apply.
major	Row count for row pointers; column count for column pointers. Integer 0–127.	A finite safe integer within the operation’s stated bounds.
minor	Opposite-axis size, an integer 0–128.	A finite safe integer within the operation’s stated bounds.

Output field	Interpretation
result	Object containing the named fields below.
result.valid	True after the layout/record validation succeeds; malformed input causes an error.
result.entries	Number of explicitly stored entries, including duplicate and zero records.
result.emptyMajorIndexes	Zero-based rows or columns whose adjacent pointers are equal.

json

{
  "input": {
    "pointers": [
      0,
      0,
      1
    ],
    "indexes": [
      1
    ],
    "values": [
      2
    ],
    "major": 2,
    "minor": 2
  },
  "output": {
    "result": {
      "valid": true,
      "entries": 1,
      "emptyMajorIndexes": [
        0
      ]
    }
  }
}

Limitations and assumptions

An invalid layout raises an error rather than returning false; duplicates and unsorted indexes are allowed.
Triplets are JSON records with row, column and value. Coordinate shapes are ordinarily bounded to 128 per axis; compressed major dimensions are limited to 127 for pointer-list capacity. The dense-budget operation has separate larger shape limits and returns exact counts as decimal text.
Every declared top-level input field is required and unexpected fields are rejected. Ordinary strings are limited to 8,192 UTF-16 code units and lists to 128 entries, with tighter operation-specific bounds where stated. JSON text has bounded nesting and node counts.
Numeric outputs must be finite and no larger in absolute magnitude than the safe-integer limit; operations returning exact large integers use decimal text. Positions are zero-based and spans end exclusively unless the operation explicitly states a different convention.

Alternative or Complementary methods

Distinguish stored-record counts, coordinate-pattern checks and arithmetic matrix properties. Combine duplicates or prune zeros explicitly when required, and use a matrix library for numerical linear algebra.

References

Tool behavior and example: Sparse Row Pointer Layout Validator — tool.io

Similar or alternative tools

Sparse Column Pointer Layout Validator
Validate CSC pointer arity, monotonicity, final entry count and minor bounds; duplicates/unsorted minor indexes remain legal observations.
Sparse Coordinate Row Pointer Builder
Build stable CSR row pointers and aligned column/value/source-index arrays from COO observations; no duplicate combination or per-row column sorting.