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Random One-Hot Index Mask

Replay seed or one advancing injected source, uniform over the explicitly stated finite support, not cryptographically secure. Choose one uniform left-to-right bit index and return its one-hot text mask; no integer endianness inference.

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Description

Choose one uniform left-to-right bit index and return its one-hot text mask; no integer endianness inference.

A random construction is defined by its sampling support: positions, permutations, complete tilings, proposal sequences or another explicit set. Uniform choices at one stage do not necessarily make final visible outcomes uniform. A replay seed gives a deterministic sequence; equal values can hide different sampled positions. These tools are for reproducible synthetic examples rather than cryptographic entropy.

Choose one uniform left-to-right bit index and return its one-hot text mask; no integer endianness inference.

When to use this tool

Use this tool to choose one uniform left-to-right bit index and return its one-hot text mask; no integer endianness inference.

How to use the tool and how it works

  1. Enter width, seed using the definitions below.
  2. Run the operation. Resolve input-format errors before interpreting an output.
  3. Read result.seed, result.index, result.mask, using the stated boundary, ordering, sign and absence conventions.

Require width 1–128, draw one index uniformly and return a width-character binary string with a one only at that index.1

Input fieldMeaning and unitsAccepted input
widthInteger width, 1–128, in the positions/cells described above.Finite safe integer satisfying the stated bounds.
seedNonblank replay seed, at most 256 UTF-16 code units; an injected source overrides seeded draws.Text, at most 8,192 UTF-16 code units; narrower grammar/range rules also apply.
Output fieldInterpretation
resultObject containing the fields below.
result.seedOriginal supplied seed string; injected-source replay additionally requires that source’s state.
result.indexZero-based selected source position.
result.maskLeft-to-right 0/1 text mask of the requested width.
json
{
  "input": {
    "width": 4,
    "seed": "batch56"
  },
  "output": {
    "result": {
      "seed": "batch56",
      "index": 2,
      "mask": "0010"
    }
  }
}

Limitations and assumptions

  • String position zero is the leftmost character; the mask is text, not an integer with an inferred bit-endian convention.
  • A nonblank seed of at most 256 UTF-16 code units is required. With ordinary use the seed initializes one deterministic advancing source; an application-injected random source takes precedence and the seed alone then cannot replay the result. Uniformity statements assume independent uniform source draws in [0,1). Source calls are bounded and degenerate injected sources can fail a rejection budget. This is not cryptographically secure.
  • Every declared outer field is required and unknown outer fields are rejected. Strings and JSON text have size limits, lists are bounded to 128 entries, and JSON nesting/node counts are bounded. Tighter operation-specific bounds stated above take precedence.
  • Ordinary numeric outputs must be finite and within safe-integer magnitude. Exact large lengths/counts use decimal strings. Original record indexes and code-unit positions are zero-based; span ends are exclusive unless stated otherwise.

Alternative or Complementary methods

Choose a generator whose support matches the intended experiment and retain source-position provenance. Use a separate statistically justified process model or cryptographic source where those properties matter.

References

  1. Tool behavior and example: Random One-Hot Index Mask — tool.io

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