Trait differential_dataflow::algorithms::prefix_sum::PrefixSum

pub trait PrefixSum<G: Scope, K, D> {
    // Required methods
    fn prefix_sum<F>(&self, zero: D, combine: F) -> Self
       where F: Fn(&K, &D, &D) -> D + 'static;
    fn prefix_sum_at<F>(
        &self,
        locations: Collection<G, (usize, K)>,
        zero: D,
        combine: F,
    ) -> Self
       where F: Fn(&K, &D, &D) -> D + 'static;
}

Extension trait for the prefix_sum method.

Required Methods

fn prefix_sum<F>(&self, zero: D, combine: F) -> Self

where F: Fn(&K, &D, &D) -> D + 'static,

Computes the prefix sum for each element in the collection.

The prefix sum is data-parallel, in the sense that the sums are computed independently for each key of type K. For a single prefix sum this type can be (), but this permits the more general accumulation of multiple independent sequences.

fn prefix_sum_at<F>( &self, locations: Collection<G, (usize, K)>, zero: D, combine: F, ) -> Self

where F: Fn(&K, &D, &D) -> D + 'static,

Determine the prefix sum at each element of location.

Object Safety

This trait is not object safe.

Implementors

impl<G, K, D> PrefixSum<G, K, D> for Collection<G, ((usize, K), D)>

where G: Scope, G::Timestamp: Lattice, K: ExchangeData + Hash, D: ExchangeData + Hash,