Function apply_local_update_sweep 

pub fn apply_local_update_sweep<T, V, U>(
    treetn: &mut TreeTN<T, V>,
    plan: &LocalUpdateSweepPlan<V>,
    updater: &mut U,
) -> Result<()>
where
    T: TensorLike,
    <T::Index as IndexLike>::Id: Clone + Hash + Eq + Ord + Debug + Send + Sync,
    V: Clone + Hash + Eq + Ord + Send + Sync + Debug,
    U: LocalUpdater<T, V>,

Apply a local update sweep to a TreeTN.

This function orchestrates the sweep by:

1. Iterating through the sweep plan
2. For each step: a. Validate that the canonical center is a single node within the extracted subtree b. Extract the local subtree c. Call the updater to transform it d. Replace the subtree back into the TreeTN

Arguments

• treetn - The TreeTN to update (modified in place)
• plan - The sweep plan specifying the update order
• updater - The local updater implementation

Preconditions

• The TreeTN must be canonicalized with a single-node canonical center
• The canonical center must be within the first step’s nodes

Returns

Ok(()) if the sweep completes successfully.

Errors

Returns an error if:

• TreeTN is not canonicalized (canonical_region is empty)
• canonical_region is not a single node
• canonical_region is not within the extracted subtree
• Subtree extraction fails
• The updater returns an error
• Subtree replacement fails