FA-97778 / Knitting and sewing pattern grading / Member archive

Top-down raglan setup: odd leftover placement · case 03

An odd neck count loses a stitch in the split.

Member previewVariant 3 · 3 implementations · 8 checks per implementation

Case contract

neck_sts < 16 -> "error: neck too small". Reserve 4 raglan seam stitches; rem = neck-4; front = rem//3; sleeves share rem - 2*front, each sleeve half of that, and an odd leftover goes to the back (back = front + leftover%2). Each increase round adds 2 to front (and back); rounds = max(0, ceiling((underarm_body_sts//2 - front)/2)). yoke_total = neck + 8*rounds.

Why this case matters

Top-down raglan sweaters split the neck cast-on among front, back, sleeves and seam stitches.

One recorded failure

Sample boundary fixture

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

Boundary fixture	Actual	Expected	Outcome
regression: odd leftover placement	`{"back": 32, "front": 32, "increase_rounds": 34, "raglan": 4, "sleeve": 16, "yoke_total": 373}`	`{"back": 33, "front": 32, "increase_rounds": 34, "raglan": 4, "sleeve": 16, "yoke_total": 373}`	Failed

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