Struct LocalOps 

pub struct LocalOps<T: FloatExt + Hash> {
    pub interval: (usize, usize),
    pub padding: RankOneTwo<T>,
    pub idx_to_mat: BTreeMap<usize, RankOneTwo<T>>,
}

Represents a tensor product of local 2×2 complex operators acting on specific qubit indices.

This structure encodes a sparse tensor product of single-qubit operators. Each mapped entry specifies a RankOneTwo<T> acting on a particular qubit index. The full operator is constructed as an ordered tensor product over a specified interval of qubit indices. Indices not explicitly mapped use the provided padding operator.

This is useful for compactly representing structured operators such as Kraus operators.

Fields

interval: (usize, usize)

Inclusive interval of qubit indices spanned by the tensor product: [start, end].

padding: RankOneTwo<T>

Default RankOneTwo<T> used for unmapped qubit indices within the interval.

idx_to_mat: BTreeMap<usize, RankOneTwo<T>>

Mapping from selected qubit indices to non-default local operators.

Implementations

impl<T: FloatExt + Hash> LocalOps<T>

pub fn indices_keys(&self) -> Vec<usize>

Returns the list of qubit indices that have explicitly assigned RankOneTwo.

pub fn try_interval(&self) -> (Option<usize>, Option<usize>)

Returns the inclusive interval of explicitly assigned qubit indices, if any.

This is equivalent to (min_index, max_index) over the idx_to_mix map. Returns (None, None) if the map is empty.

pub fn try_fit_interval(&self) -> Option<Self>

Returns a new LocalOps with its interval adjusted to match the minimum and maximum keys present in the idx_to_mat map.

This method is useful for automatically syncing the interval field with the actual span of explicitly defined qubit indices.

Returns

• Some(Self) with the updated interval if idx_to_mat is non-empty.
• None if idx_to_mat is empty, as there are no keys to determine an interval.

pub fn extract_padding(&self) -> Self

Returns a new LocalOps where all indices in the interval are explicitly filled.

For any index within self.interval that does not appear in idx_to_mat, this method inserts an entry with the padding value. The result is a fully populated BTreeMap with no missing indices in the defined interval.

pub fn set_interval(&self, interval: (usize, usize)) -> Self

Returns a new LocalOps with the specified interval, leaving all other fields unchanged.

This method updates the interval field while cloning the existing padding and idx_to_mat map.

pub fn set_padding(&self, padding: RankOneTwo<T>) -> Self

Returns a new LocalOps with the specified padding value, leaving the interval and index-to-mat map unchanged.

pub fn discard<I: IntoIterator<Item = usize>>(&self, indices: I) -> Self

Returns a new LocalOps with the specified indices removed from idx_to_mat.

This method creates a copy of the current structure and removes any entries whose keys match the provided indices. The original interval and padding are preserved.

Type Parameters

• I: An iterable collection of usize indices to remove.

Arguments

• indices: Any iterable over usize values (e.g., a Vec, array, range, or HashSet).

Returns

A new LocalOps with the specified indices removed from the map.

Examples

//let pruned = original.discard(vec![1, 2, 4]);
//let pruned = original.discard([3, 5, 7]);
//let pruned = original.discard(0..=10);

pub fn extend(&self, idx_to_mat: BTreeMap<usize, RankOneTwo<T>>) -> Self

Returns a new LocalOps with additional entries merged into idx_to_mat.

For each (index, RankOneTwo<T>) in the provided idx_to_mat map, if the index is not already present in the current map, it is inserted. Existing entries are left unchanged.

The resulting interval is updated to span the full range of indices in the combined map, unless the map becomes empty, in which case the original interval is retained.

Arguments

• idx_to_mat - A BTreeMap<usize, RankOneTwo<T>> containing new entries to insert.

Returns

A new LocalOps with the merged map and updated interval.

pub fn force_update(&self, idx_to_mat: BTreeMap<usize, RankOneTwo<T>>) -> Self

Returns a new LocalOps with the given entries forcibly updated.

For each (index, RankOneTwo<T>) in the provided map:

• Any existing entry at that index is removed.
• The new entry is inserted unconditionally.

The updated idx_to_mat map reflects all changes, and the interval is recomputed to span the full range of keys present in the new map (if non-empty).

Arguments

• idx_to_mat - A BTreeMap<usize, RankOneTwo<T>> containing entries to overwrite.

Returns

A new LocalOps with the forcibly updated entries and recalculated interval.

pub fn swap(&self, i: usize, j: usize) -> Self

Returns a new LocalOps with the values at two indices swapped.

If both indices exist in idx_to_mat, their values are swapped. If only one exists, its value is moved to the other index. If neither exist, the mapping is unchanged.

Arguments

• i - The first index.
• j - The second index.

Trait Implementations

impl<T: Clone + FloatExt + Hash> Clone for LocalOps<T>

fn clone(&self) -> LocalOps<T>

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<T: Debug + FloatExt + Hash> Debug for LocalOps<T>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<T: Hash + FloatExt + Hash> Hash for LocalOps<T>

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl<T: PartialEq + FloatExt + Hash> PartialEq for LocalOps<T>

fn eq(&self, other: &LocalOps<T>) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl<T: Eq + FloatExt + Hash> Eq for LocalOps<T>

impl<T: FloatExt + Hash> StructuralPartialEq for LocalOps<T>