Bloom Filter Sizing Calculator implementation

Binding contract

This record describes what an executable surface must bind and validate. It does not claim that a public calculator, package, or production route is deployed.

Record owner

Guth Instruments

Lifecycle

verified-clean

Evidence ID

t5-134

Effect

Computation or source lookup only

Input and validation requirements

The specification permits boundary and zero-item inputs for which k or the actual false-positive rate is undefined, and it does not state whether p is a fraction or a percentage. A plain arithmetic implementation that lacks validation or an explicit unit convention can return misleading zeroes, NaN, or degenerate results.

Required corrections

No binding erratum is attached to this unique-name record. Implementers must still preserve the declared units, domain, and failure behavior.

Inspectable interface fixture

The sample below is evidence for interface and validation tests, not a production implementation.

{
  "inputs": {
    "n": 1000,
    "p": 0.01
  },
  "expected_outputs": {
    "m": 9585.058377,
    "k": 6.64385619,
    "actual_false_positive_rate": 0.01
  },
  "working": "ln(0.01)=-4.605170186; ln(2)^2=0.480453014. m=-(1000×-4.605170186)/0.480453014=4605.170186/0.480453014=9585.058377 bits. k=(9585.058377/1000)×0.693147181=6.64385619. Ideal FPR=(1-exp(-(6.64385619×1000)/9585.058377))^6.64385619=(1-exp(-0.693147181))^6.64385619=(1-0.5)^6.64385619=0.5^6.64385619=0.01."
}

Other records

Sources and evidence

These pointers bind the page to evidence. They do not grant authority or collapse verification into deployment.

• VERIFIED_LEDGER.json
• evidence-tranche5/tranche5-results.json