Unit Converter — Physics Quantities mechanism

Model scope

The stated algorithm is standard for compatible, multiplicative physics units, but the specification is not sufficiently precise to certify the instrument. Supply a versioned factor table, define all unit conventions and significant-digit/rounding behavior, and specify rejection behavior for incompatible, offset, and logarithmic units.

• Linear scale-factor multiplication is correct for conversions between compatible linear units, but the specification does not provide the actual conversion-factor table needed for verification.
• The converter must enforce dimensional compatibility; converting between incompatible quantity types must be rejected rather than applying an arbitrary factor.
• The specification does not define conventions for ambiguous units such as calorie, light-year, parsec, and amu, nor the precision and rounding policy for returned values.
• A purely linear model does not cover offset units such as degrees Celsius/Fahrenheit or logarithmic units such as decibels; these must be explicitly excluded or handled separately.

Units and conventions

• eV uses the exact SI elementary-charge relation: 1 eV = 1.602176634e-19 J.
• 1 J = 1e7 erg exactly by the SI-to-cgs definition.
• 1 AU = 149597870700 m exactly (IAU nominal astronomical unit).
• 1 pc = (648000/pi) AU, using the IAU parsec definition and pi = 3.141592653589793.
• The zero-calorie test is independent of the calorie convention; nonzero calorie conversions require an explicit choice such as thermochemical calorie, 1 cal_th = 4.184 J.
• The amu, if supported, should mean the unified atomic mass unit (dalton), not an alternative historical atomic-mass convention.

Inspectable vector

One of 4 source-bound review vectors:

{
  "inputs": {
    "quantity_type": "energy",
    "value": 0,
    "from_unit": "cal",
    "to_unit": "J",
    "calorie_convention": "thermochemical"
  },
  "expected_outputs": {
    "value": 0,
    "unit": "J"
  },
  "working": "1. Apply the linear conversion: J = cal × 4.184 J/cal. 2. J = 0 × 4.184 = 0 J. This is an edge case and gives the same result for any calorie convention."
}

Failure boundary

BREAK_CLAIMED · SELF_FLAGGED

An extreme but representable input value, 1e308 J, converts mathematically to approximately 6.241509074460763e326 eV and overflows a JavaScript IEEE-754 Number to Infinity. The calorie probe also exposes a convention-dependent result if the lookup table does not specify the calorie definition.

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-tranche6/tranche6-results.json
• BOUNDARY_HAZARD_CATALOG.json