Function unit_square_boundary_distributed 

pub fn unit_square_boundary_distributed<T: Scalar + Equivalence, C: Communicator>(
    comm: &C,
    partitioner: GraphPartitioner,
    nx: usize,
    ny: usize,
    cell_type: ReferenceCellType,
) -> ParallelGridImpl<'_, C, SingleElementGrid<T, CiarletElement<T, IdentityMap, T>>>

Create a grid of the boundary distributed in parallel