Function cungbr_buffer_size 

pub fn cungbr_buffer_size(
    ctx: &Context,
    side: SideMode,
    m: usize,
    n: usize,
    k: usize,
    a: &DeviceMemory<Complex32>,
    lda: usize,
    tau: &DeviceMemory<Complex32>,
) -> Result<usize>