Struct FaMain 

pub struct FaMain { /* private fields */ }

One fa-decode main node with its paired combine — the per-token geometry-update unit.

Both classes get the FULL update (grid.y + n_splits arg + paired combine’s n_splits): the partial buffers are zeros() allocations whose memset is CAPTURED — every replay re-zeroes them, so any split slot the main doesn’t write holds m=0.0 (NOT the NEG_INF empty the combine skips). The combine’s merge count must therefore exactly equal the main’s written split count. n_splits is simultaneously the key partition and the partial stride in every fa kernel, so main + combine move as one value:

• vec dc twins (fa_decode_vec_q*_dc): per = ceil(T_kv/n_splits), arg idx 11; the live count comes from the caller’s split ladder (eager lockstep).
• scalar unified (fa_decode_f32, ctr non-null): ns_eff = ceil(T_kv/split_keys) in- kernel; setting n_splits (idx 12) = that same value keeps stride == partition.

Trait Implementations

impl Send for FaMain