Public evidence

math.percent_error

Machine-checked verification for calculation version 1.1.4 · tier engine_tested

Open calculator API Capability Download JSON CVP Manifest Reproduce MCP Review policy

Historical evidence. This page is version 1.1.4 · engine_tested · 14/14 tests. It is not the current published claim. Current evidence is 1.2.0 (14/14 tests) · latest.

CVP status

T≠0; solve_for p|o|t; all three fields verify; absolute reverse-solves are multi-valued

Declared partition coverage: PASS · 5/5 declared partitions (forward, inverse-observed, inverse-true, verify, invalid-domain)
Versions: Calculation 1.1.4 · CVP protocol 1.0.0-proposed · Evidence 2026-10-13.percent-error-replay-review
Verification revision: 2026-10-13.percent-error-replay-review · 3/3 property · digest 630a2997f606

Verification

Legacy regression suite: 14/14 calculation tests · Production surface contract 5/5

Three distinct suites: educational examples on the calculator page, this legacy regression count (14/14 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 1.2.0 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.percent-error-replay-review. Calculation version 1.1.4. CVP 1.0.0-proposed. 22/22 golden · 4/4 CVP boundary · 12/12 invalid · 3/3 property · 1/1 metamorphic · 7/7 round-trip · 30/30 cross-interface · 5/5 CVP contract. digest 630a2997f606.

Golden (oracle-backed) 22 / 22
CVP boundary 4 / 4
Invalid input 12 / 12
Property 3 / 3
Metamorphic 1 / 1
Round-trip 7 / 7
Cross-interface 30 / 30
CVP contract 5 / 5
Interfaces PASS · UI (SSR) / REST / MCP
Interface claim ui-ssr is query-result HTML, not a live browser session. Error-path engine·REST·MCP 8/8 (status, code, calculation_version). SSR compared on URL-canonical requested calculations; empty query is idle (not an error) and JSON-typed object/array inputs are REST/MCP-only.
Assurance Engineering

release artifacts aligned PASS
schema output required declared PASS
schema valid input executes PASS
engine success output validates schema PASS
rest success payload validates schema PASS

Fingerprint sha256:783cd14e12cb9811044d6bc3fce9d6c1f6fd3cf96201ae81a3916d8ad4aad9f1

Input schema sha256:9e03727ba37a3e2ed408e1b5848d278926befd7c7560784f476b13b239ba0ac9 · Output schema sha256:1ffdaff2555960cc04fef346c1146c38f6a8feb12995a9fdb488e220d00a439c · 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: percent-error
Engine: percent-error
Engine build: 2026-10-14
Evidence core: 2026-10-14T02:50:33.742Z
Rendered: 2026-10-22T01:03:27.742Z
Last reviewed: —

Assumptions

Interactive evaluation runs locally in the browser. Shared URLs and REST may evaluate the same versioned engine on the server (query SSR).
Accepted value T ≠ 0.
Default formula uses absolute value so % error ≥ 0.
Exactly two fields are inputs. Explicit solve_for selects the output. If all three are supplied without solve_for, they are checked for consistency rather than overwritten.

Limitations

T = 0 → TRUE_VALUE_ZERO
Inconsistent triples may return status inconsistent
Reverse solve edge cases → NO_REAL_SOLUTION / INFINITELY_MANY

Sources

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

JCGM 200:2012 — International vocabulary of metrology (VIM) — §2.16 measurement error
Supports: Defines measurement error as measured quantity value minus a reference quantity value (ε = O − T). Does not define relative error — VIM §2.18 is measurement bias, not relative error. Does not prescribe a percent-error ×100% laboratory convention.
NIST Dataplot PERCERR — Percent error of a true/accepted value vs an observed value
Supports: Documents percent error from an accepted (true) value and an observed value, and notes that some conventions take the absolute value. Instantly readable page — not the frameset handbook root.
NIST Dataplot RELERR — Relative error of a true/accepted value vs an observed value
Supports: Documents relative error (Xt − Xo)/Xt. Notes that some sources take the absolute value, and some reverse numerator order — those change sign, not magnitude.
CalculatorX laboratory convention — Absolute-value percent error, signed opt-in, and reverse-solve states
Supports: Default % error = |O−T|/|T|×100% so the result is ≥ 0; signed (O−T)/T×100% is opt-in. Displayed absolute error is |ε|, the magnitude of VIM measurement error — not a separate VIM term. Absolute reverse-solves publish both ± candidates, omit a zero-denominator branch, and publish INFINITELY_MANY when every T ≠ 0 works. Signed P = −100% with O ≠ 0 is NO_REAL_SOLUTION.

Verification disclosure

Aggregate outcomes, scope and artifact commitments are public. Complete test inputs, expected values, execution records and oracle infrastructure are retained privately. This summary does not independently reproduce the full verification run.