83d633798f
agent_radix_sort_upsweep.cuh (517 lines) key insight: UNROLL_COUNT = min(64, 255/KEYS_PER_THREAD) — limits accumulation steps to prevent unsigned char counter overflow Same principle applied to GatedDeltaNet cumsum: chunk=64 + pre_clamp_max=2.0 → worst cumsum = 128 → exp(128) = inf chunk=16 + pre_clamp_max=2.0 → worst cumsum = 32 → clamp(-20,20) safe This was the remaining NaN source: clamp at [-5,2] before cumsum was necessary but not sufficient when chunk_size=64.