Function orgqr 

pub fn orgqr<T: SolverScalar>(
    handle: &DnHandle,
    m: i32,
    n: i32,
    k: i32,
    a: &mut DeviceBuffer<T>,
    lda: i32,
    tau: &DeviceBuffer<T>,
    info: &mut DeviceBuffer<i32>,
) -> Result<()>

Generate the orthogonal matrix Q from the factorization produced by geqrf. After this, a holds the first n columns of Q.