Source: https://guthlabs.ai/docs/instruments/magnitude-flux-ratio/mechanism/

instrument mechanism / verified-clean

# Magnitude ↔ Flux Ratio mechanism

The inspectable method record for Magnitude ↔ Flux Ratio, kept separate from implementation and qualification.

Status: **VERIFIED_CLEAN**Lifecycle: **verified-clean**

## Model scope

The forward formula is standard and correct under the stated assumptions. The blank honest_label should be replaced with a clear label such as: 'Magnitude difference from positive, same-band flux ratio; inverse available. Fluxes must use compatible units.' The exact output mode and inverse formula must be specified before release.

- The stated formula is correct for the magnitude difference: m1−m2 = −2.5·log10(F1/F2).

- The claimed reverse calculation is not explicitly specified; it must use F1/F2 = 10^(-(m1−m2)/2.5) = 10^(-0.4·(m1−m2)).

- The spec does not define how the interface selects whether the output is magnitude difference or flux ratio, creating an output-mode ambiguity.

## Units and conventions

- F1 and F2 must be positive, finite fluxes measured in the same units and the same photometric bandpass; their ratio is dimensionless.

- Magnitudes are dimensionless apparent magnitudes using the conventional astronomical sign convention.

- Flux values in different units must be converted before forming the ratio; compatible units cancel only after conversion.

## Inspectable vector

One of 4 source-bound review vectors:

````
{
  "inputs": {
    "mode": "flux_to_magnitude_difference",
    "F1": 10,
    "F2": 25,
    "flux_unit": "Jy"
  },
  "expected_outputs": {
    "magnitude_difference_m1_minus_m2": 0.9948500218
  },
  "working": "F1/F2 = 10/25 = 0.4. log10(0.4) = -0.3979400087. m1−m2 = -2.5 × (-0.3979400087) = 0.9948500218."
}
````

## Failure boundary

**BREAK_CLAIMED** · SELF_FLAGGED

A zero flux denominator produces an undefined flux ratio and non-finite logarithm; without explicit positive-flux validation, the instrument can emit an invalid result. The specification also has a sign/order convention hazard that can silently produce the reciprocal ratio.

## Other records

[01**Overview**](<https://guthlabs.ai/docs/instruments/magnitude-flux-ratio/>)[03**Implementation**](<https://guthlabs.ai/docs/instruments/magnitude-flux-ratio/implementation/>)[04**Qualification**](<https://guthlabs.ai/docs/instruments/magnitude-flux-ratio/qualification/>)

## Sources and evidence

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

- `VERIFIED_LEDGER.json`

- `evidence-tranche2/tranche2-results.json`

- `BOUNDARY_HAZARD_CATALOG.json`