FA-55907 / Astronomical coordinate conventions / Member archive

Nested sky cell address: Nested sky descendant range expands by a linear or binary scale · case 02

The adapter reports an incorrect descendant first while other fields remain valid.

Member previewVariant 2 · 3 implementations · 6 checks per implementation

Case contract

A stipulated hierarchical sky tessellation has 12 base faces and four nested children per cell. At order o a face has 4**o pixels. p is the local pixel index, f the face, k the child digit. Parent and descendant ranges are nested indexing operations; no geometric HEALPix projection is implemented. Output fields are defined by: global_pixel = d['f']*4**d['o']+d['p']; parent_local = d['p']//4; child_local = 4*d['p']+d['k']; descendant_first = d['p']*4**d['depth']; descendant_stop = (d['p']+1)*4**d['depth']; face_count = 12*4**d['o']

Why this case matters

Catalog, detector, sky-coordinate, and spectroscopy adapters must preserve the association between numeric coordinates and their declared reference conventions.

One recorded failure

Sample boundary fixture

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

Boundary fixture	Actual	Expected	Outcome
astronomical fixture 0	`{"child_local": 26, "descendant_first": 12, "descendant_stop": 112, "face_count": 192, "global_pixel": 54, "parent_local": 1}`	`{"child_local": 26, "descendant_first": 96, "descendant_stop": 112, "face_count": 192, "global_pixel": 54, "parent_local": 1}`	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.