FA-16648 / Floating-point arithmetic / Member archive

Exact ratio conversion assigns sign to the denominator · case 03

Exact ratio conversion assigns sign to the denominator.

Member previewVariant 3 · 3 implementations · 11 checks per implementation

Case contract

Decode a finite binary64 value into its exact reduced signed numerator and positive power-of-two denominator, using (0,1) for either zero. Infinity and NaN return null.

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
negative subnormal	`[3, -202402253307310618352495346718917307049556649764142118356901358027430339567995346891960383701437124495187077864316811911389808737385793476867013399940738509921517424276566361364466907742093216341239767678472745068562007483424692698618103355649159556340810056512358769552333414615230502532186327508646006263307707741093494784]`	`[-3, 202402253307310618352495346718917307049556649764142118356901358027430339567995346891960383701437124495187077864316811911389808737385793476867013399940738509921517424276566361364466907742093216341239767678472745068562007483424692698618103355649159556340810056512358769552333414615230502532186327508646006263307707741093494784]`	Failed

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