Function potrs 

pub fn potrs<T: SolverScalar>(
    handle: &DnHandle,
    uplo: Fill,
    n: i32,
    nrhs: i32,
    a: &DeviceBuffer<T>,
    lda: i32,
    b: &mut DeviceBuffer<T>,
    ldb: i32,
    info: &mut DeviceBuffer<i32>,
) -> Result<()>

Solve A * X = B using the Cholesky factorization from potrf.