Function ba_gates_output 

pub fn ba_gates_output(group: u32, local_out: u32) -> u32

2026-09-25: The BA output a thread owns: group * BA_GATES_OUTS + local_out. The parent’s group is blockIdx.x; the twin’s is g0 + g, walking 0..ceil(N/4) in tiles of BA_GATES_GROUPS.