Runtime.NativeDataParallelOwnedTree

Per-coordinate ownership (Runtime.NativeDataParallelOwned: optimizer state and, with p = 1, parameters) over a bounded-fan-out hierarchy (Representation.ParticipantTree) instead of a star: combine: the sum and the assembly run on the hierarchy's tree (Runtime.NativeCombine), so a participant exchanges with at most fanout + 1 peers per combine; publication: Checkpoint.NativeTreePublication. Every owner writes the shards of its own words (its coordinates' optimizer state and, when partitioned, parameters); the root also writes the replicated words (replicated parameters, shared state). Each commitment carries the child's capture prefix and replicated words, which the parent compares with its own, so diverged replicas publish no root, and no owner ever holds another owner's words; restore: every owner reads its manifest path, its own shards and, below the root, only the root's replicated shards. The checkpoint's identity is the star's for replicated parameters with the hierarchy's combine order, and for partitioned parameters the learner's placement-independent identity tagged with the hierarchy's manifest tree.

61field unrestricted dataParallelOwnedTreeRootShards : (family NativeRegionCheckpoint)