Struct opendp::metrics::HammingDistance

pub struct HammingDistance;

The number of elements that differ between two equal-length datasets.

This metric is sensitive to data ordering. Since this metric counts the number of changed rows, it is a bounded metric (for bounded DP).

Since this metric is bounded, the dataset size must be fixed. Thus we only consider neighboring datasets with the same fixed size: crate::domains::VectorDomain::size.

Proof Definition

d-closeness

For any two datasets $u, v \in \texttt{D}$ and any $d$ of type IntDistance, we say that $u, v$ are $d$-close under the Hamming distance metric (abbreviated as $d_{Ham}$) whenever

d_{Ham}(u, v) = \#\{i: u_i \neq v_i\} \leq d

Note

The distance type is hard-coded as IntDistance, so this metric is not generic over the distance type like many other metrics.

WLOG, most OpenDP interfaces need only consider unbounded metrics. Use crate::transformations::make_metric_unbounded and crate::transformations::make_metric_bounded to convert to/from the symmetric distance.

Compatible Domains

• VectorDomain<D> for any valid D, when VectorDomain::size.is_some().

Trait Implementations

impl BoundedMetric for HammingDistance

type UnboundedMetric = InsertDeleteDistance

impl Clone for HammingDistance

fn clone(&self) -> HammingDistance

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for HammingDistance

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

Formats the value using the given formatter.

impl Default for HammingDistance

fn default() -> Self

Returns the “default value” for a type.

impl Metric for HammingDistance

type Distance = u32

Proof Definition

impl OrderedMetric for HammingDistance

type UnorderedMetric = ChangeOneDistance

impl PartialEq<HammingDistance> for HammingDistance

fn eq(&self, _other: &Self) -> bool

This method tests for self and other values to be equal, and is used by ==.

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

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