FA-17008 / Floating-point arithmetic / Member archive

Log divided difference subtracts logarithms of adjacent large values · case 03

Log divided difference subtracts logarithms of adjacent large values.

Member previewVariant 3 · 3 implementations · 10 checks per implementation

Case contract

Evaluate (log(b)-log(a))/(b-a) for positive finite endpoints with continuous limit 1/a. Close ratios use log1p; fixtures have finite outputs. Finite results are rendered to eleven significant decimal digits; modeled domain violations and arithmetic errors are explicit strings.

Why this case matters

An offline floating representation model isolates a reproducible arithmetic fault.

One recorded failure

Sample boundary fixture

This sample comes from the broken implementation of a controlled reproducer.

Boundary fixture	Actual	Expected	Outcome
close large	`"0"`	`"1e-100"`	Failed

MEMBER ARCHIVE

The complete case is available to members.

This record includes three runnable implementations, regression fixtures, execution results, and source hashes.

Member access is invitation-based. Sign in with your invited account to inspect the sources.