math.log

Three distinct suites: educational examples on the calculator page, this legacy regression count (45/45 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.

This calculator CURRENT · Public schema 1.1.6 matches · Semantic contract ✓ · Production attested · Public/cache ✓ · Origin ✓

CVP verification suite

Protocol checks from the Evidence Manifest. Distinct from the legacy regression suite above. Verification revision 2026-10-27.full-review-v3. Calculation version 1.1.6. CVP 1.0.0-proposed. 48/48 golden · 23/23 CVP boundary · 23/23 invalid · 2/2 property · 2/2 metamorphic · 3/3 round-trip · 14/14 O3 · 6/6 cross-interface · 12/12 cross-calculator · 4/4 URL→result→graph · 6/6 CVP contract. digest a3170216f569. ≤2 ULP vs O3 applies to the 14 published tabulated common-log vectors (log₁₀ of 1, 10, 100, 0.1, 2, 1000 plus 8 seeded random x = 10^(u·6−2) in about [0.01, 10⁴]). It is not a guarantee over all bases, the whole positive reals, or unlisted neighborhoods of 0 and 1.; plus45 independent Decimal200 complete packs:4ULP forward/argument and128ULP solved base, known inputs exact. No whole-domain guarantee.

• Golden (oracle-backed) 48 / 48
• CVP boundary 23 / 23
• Invalid input 23 / 23
• Property 2 / 2
• Metamorphic 2 / 2
• Round-trip 3 / 3
• O3 high-precision 14 / 14
• Cross-interface 6 / 6
• Cross-calculator 12 / 12
• URL → result → graph 4 / 4
• CVP contract 6 / 6
• Interfaces PASS · UI (SSR) / REST / MCP / URL→result→graph
• Interface claim Success 3/3. Error-path engine·REST·MCP 3/3 (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. Integration: URL → SSR result → Live graph current point (4/4). Hydration/slider/history are URL-canonical contracts, not a live browser session.
• Assurance Core

• 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
• rest success payload validates schema PASS

Fingerprint sha256:36ea10b0e2113c1354027bdab7d5812f7c7426207fc2a5df8dac68d7430801ab

Input schema sha256:a1a6766ec07f567848082fb89fb3c34dce8aaa0b252f8702931fc74fe395bf24 · Output schema sha256:b069e80c0bb536f1b63e7806faa1ab2dd1aea918a5d35c5abaf997f5df7e611a · 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.

Tool

log

Engine

log

Engine build

2026-10-27

Evidence core

2026-10-27T02:30:37.745Z

Rendered

2026-10-28T03:01:57.866Z

Last reviewed

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Assumptions

• Real arithmetic; argument x > 0; base b > 0 and b ≠ 1.
• Unspecified log is common (base 10). ln is the dedicated natural-log page; this engine also accepts base e.
• UI, SSR share URLs, REST, and validation cases all call this same three-mode engine.
• When b, x, and y are all present with no explicit solve_for, the engine computes y and ignores the extra y (legacy share URLs).

Limitations

• Solve y=log_b(x), x=b^y or b=x^(1/y). Positive finite x and base b>0,b≠1; y finite. Omitted base defaults10 only for forward/argument solve.
• Strict decimal/scientific text up to512 characters or e; matching known-input aliases; unknown keys, nonfinite types and nonzero text rounded to zero reject. Legacy all-three selects y; requested output fields are ignored.
• No numerical snapping near1/2/e/10. Symbolic base e uses Math.log/exp; numeric bases preserve binary64 values. Base1 rounding rejects RESULT_ROUNDED_TO_ONE, distinct from no mathematical solution.
• Independent Decimal200 fixed complete-pack vectors:4ULP for logarithm/argument and128ULP for solved base; known fields exact binary64.16 existing common-log O3 vectors retain2ULP. Neither is a whole-domain guarantee.
• Display normally12 significant digits, preserving extra digits near1; complete native exports retain raw inputs. Conditioning grows near base1 and y=0 for base solve. Local typing; URL/REST/MCP send inputs and may enter logs.