Cell/Bacterial Doubling Time 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

t4-122

Effect

Computation or source lookup only

Input and validation requirements

The formulas encounter undefined results for nonpositive or zero starting counts and at exactly zero net growth. A calculator that accepts N0=0 or emits a finite doubling time when N=N0 would fail this adversarial set.

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": {
    "N0": 100,
    "N": 800,
    "elapsed_time": 6,
    "time_unit": "hours"
  },
  "expected_outputs": {
    "doubling_time": 2,
    "growth_rate_mu": 0.34657359028,
    "doublings": 3
  },
  "working": "N/N0 = 800/100 = 8. ln(8) = 2.07944154168 and ln(2) = 0.69314718056. td = 6 × 0.69314718056 / 2.07944154168 = 2 hours. μ = 2.07944154168 / 6 = 0.34657359028 h^-1. Doublings = ln(8)/ln(2) = 2.07944154168/0.69314718056 = 3."
}

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-tranche4/tranche4-results.json