FA-97393 / Knitting and sewing pattern grading / Member archive

Sleeve taper decrease schedule: decrease pair count · case 03

A 16-stitch taper is scheduled as 16 decrease rows, removing 32 stitches.

Member previewVariant 3 · 3 implementations · 8 checks per implementation

Case contract

Top-down sleeve from upper_sts to cuff_sts, decreasing 2 stitches per decrease row within rows rows. Errors: cuff wider ("error: cuff wider than upper arm"), odd difference ("error: odd difference"), rows fewer than decrease rows ("error: not enough rows"). pairs = difference/2; a = rows // pairs; y = rows - a*pairs decreases every a+1 rows, x = pairs-y every a rows. Return [[a, x], [a+1, y]] omitting a zero count; [] for no decreases.

Why this case matters

Pattern writers turn a stitch-count change over a length into "decrease every N rows X times".

One recorded failure

Sample boundary fixture

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

Boundary fixture	Actual	Expected	Outcome
regression: decrease pair count	`[[3, 30]]`	`[[6, 15]]`	Failed

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