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Public evidence

math.exponential_growth

Machine-checked verification for calculation version 1.0.8 · tier engine_tested

CVP status

CVP VERIFIED · production STALE · CVP protocol 1.0.0-proposed · Engineering assurance

periodic r > −100%; continuous uses k=ratePct; inverse solves any missing field among x₀, r, t given x(t)

Declared partition coverage
PASS · 7/7 declared partitions (forward-periodic, forward-continuous, inverse-time, inverse-x0, inverse-rate, verify, invalid-domain)
Versions
Calculation 1.0.8 · CVP protocol 1.0.0-proposed · Evidence 2026-10-13.growth-range-node22
Verification revision
2026-10-13.growth-range-node22 · 3/3 property · digest 204be80f9a80

Verification

Legacy regression suite: 20/20 calculation tests · Production surface contract 29/29

Three distinct suites: educational examples on the calculator page, this legacy regression count (20/20 golden + boundary), and the CVP verification suite below. They are not the same number. Property, metamorphic, round-trip, O3, and interface statuses/checks are recorded in the CVP Manifest . SKIP (0/0) means that suite has no published vectors.

    STALE · Build schema 1.0.8 matches page · production binding STALE · Semantic contract ✓ · Last attestation PASS · current evidence changed · re-attestation required · CVP STALE · attestation STALE — Production CURRENT withheld · Public/cache ✓ · Origin ✓

CVP verification suite

Protocol checks from the Evidence Manifest. Distinct from the legacy regression suite above. Verification revision 2026-10-13.growth-range-node22. Calculation version 1.0.8. CVP 1.0.0-proposed. 25/25 golden · 6/6 CVP boundary · 10/10 invalid · 3/3 property · 1/1 metamorphic · 3/3 round-trip · 13/13 O3 · 21/21 cross-interface · 4/4 URL→result→graph · 29/29 CVP contract. digest 204be80f9a80.

  • Golden (oracle-backed) 25 / 25
  • CVP boundary 6 / 6
  • Invalid input 10 / 10
  • Property 3 / 3
  • Metamorphic 1 / 1
  • Round-trip 3 / 3
  • O3 high-precision 13 / 13
  • Cross-interface 21 / 21
  • URL → result → graph 4 / 4
  • CVP contract 29 / 29
  • Interfaces PASS · UI (SSR) / REST / MCP / URL→result→graph
  • Interface claim Success 21/21. Integration: URL → SSR result → Live graph current point (4/4). Hydration/slider/history are URL-canonical contracts, not a live browser session.
  • Assurance Engineering
  • release artifacts aligned PASS
  • schema output required declared PASS
  • schema valid input executes PASS
  • engine success output validates schema PASS
  • schema rejects incomplete input PASS
  • input schema declares xt PASS
  • input schema accepts inverse time PASS
  • input schema accepts verify PASS
  • input schema rejects two fields PASS
  • output schema defines consistency PASS
  • input schema forward PASS
  • rest forward output schema PASS
  • rest forward consistency PASS
  • input schema forward continuous PASS
  • rest forward continuous output schema PASS
  • rest forward continuous consistency PASS
  • input schema inverse time PASS
  • rest inverse time output schema PASS
  • rest inverse time consistency PASS
  • input schema inverse x0 PASS
  • rest inverse x0 output schema PASS
  • rest inverse x0 consistency PASS
  • input schema inverse rate PASS
  • rest inverse rate output schema PASS
  • rest inverse rate consistency PASS
  • input schema verify PASS
  • rest verify output schema PASS
  • rest verify consistency PASS
  • rest success payload validates schema PASS

Fingerprint sha256:2c8dc99f1c6df7834ee885960fbc4ff30cb6aeec4aa94dca9121e0723957ab45

Input schema sha256:0deb990c7aa4333ba2eadc0828480ac0ead69f1cbcb75bdc5d3b1a7e49831f87 · Output schema sha256:ea35734c54417fc660e43c871c9049d02fa4059792cb3109aef99a631754901b · Build-time SHA-256 digests prove published artifacts agree with each other (release_integrity.scope=workspace). Production attestation GETs canonical URLs twice (public/cached view and origin), including Capability HTML, via npm run attest:production --write (published at /.well-known/calculatorx-production-attestation.json) and fails if the public Capability page advertises a different calculation_version. This is artifact consistency, not an independent immutable release log.

Build & scope

Engine identity and declared limitations.

Tool
exponential-growth
Engine
exponential-growth
Engine build
2026-10-13
Evidence core
2026-10-13T06:17:35.580Z
Rendered
2026-10-13T06:26:15.518Z
Last reviewed
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Assumptions

  • Constant rate over the interval (real populations often need logistic models long-term).
  • CalculatorX defines the periodic model domain as r > −100% so the growth factor stays positive and inverse/logarithmic solving remains well-defined.

Limitations

  • Periodic model requires r > −100% → RATE_MUST_BE_GT_MINUS_100
  • Non-finite inputs → INVALID_NUMBER

Sources

Standards and references supporting this tool specification. Methods are listed separately — they are algorithms, not bibliographic sources.

Legacy published checks

Golden and boundary cases from the legacy Evidence JSON. CVP property, metamorphic, round-trip, O3, and interface statuses/checks are recorded in the Manifest — including SKIP when a suite has no vectors.

IDKindStatusDetail
pop-90goldenpassExpected 1705.9666670848055 · Actual 1705.9666670848055
11yrgoldenpassExpected 17103.39358116314 · Actual 17103.39358116314
solve-tgoldenpassExpected 22.51708530541102 · Actual 22.51708530541102
decay-10goldenpassExpected 34.86784401000001 · Actual 34.86784401000001
negative-tgoldenpassExpected 61.39132535407591 · Actual 61.39132535407591
zero-x0goldenpassExpected 0 · Actual 0
continuous-kgoldenpassExpected 74.59123488206352 · Actual 74.59123488206352
continuous-k-neggoldenpassExpected 33.51600230178197 · Actual 33.51600230178197
double-100pctgoldenpassExpected 32 · Actual 32
half-life-50pctgoldenpassExpected 1 · Actual 1
solve-x0goldenpassExpected 16 · Actual 16
solve-rategoldenpassExpected 100 · Actual 100
verify-pop90goldenpassExpected 1705.9666670848055 · Actual 1705.9666670848055
verify-display-mismatchgoldenpassExpected value=1705.9666670848055 · Actual value=1705.9666670848055
r-minus-100boundarypassExpected RATE_MUST_BE_GT_MINUS_100 · Actual RATE_MUST_BE_GT_MINUS_100
r-below-minus-100boundarypassExpected RATE_MUST_BE_GT_MINUS_100 · Actual RATE_MUST_BE_GT_MINUS_100
solve-t-nonpositiveboundarypassExpected INVALID_INPUT · Actual INVALID_INPUT
solve-t-zero-rateboundarypassExpected INVALID_INPUT · Actual INVALID_INPUT
solve-rate-zero-tboundarypassExpected INVALID_INPUT · Actual INVALID_INPUT
boundary-eg-rateboundarypassExpected RATE_MUST_BE_GT_MINUS_100 · Actual RATE_MUST_BE_GT_MINUS_100