Function mla_q_rope_extract_batched 

pub fn mla_q_rope_extract_batched(
    gpu: &dyn GpuBackend,
    kernel: KernelHandle,
    q_full: DevicePtr,
    q_rope_out: DevicePtr,
    num_tokens: u32,
    nq: u32,
    hd: u32,
    nope: u32,
    rope: u32,
    q_dim: u32,
    stream: u64,
) -> Result<()>

2026-09-25: Copy each head’s rope slice (offset nope in the head’s hd) out of Q, rows q_dim apart, into contiguous [num_tokens, nq, rope].