Function potri 

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

Compute A = (Lᵀ * L)⁻¹ or A = (U * Uᵀ)⁻¹ given the Cholesky factor already stored in the triangle selected by uplo. a must hold the output of potrf in-place.