Trait differential_dataflow::algorithms::prefix_sum::PrefixSum

pub trait PrefixSum<G: Scope, K, D> {
    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.

Implementors

• impl<G, K, D> PrefixSum<G, K, D> for Collection<G, ((usize, K), D)> where     G: Scope,     G::Timestamp: Lattice,     K: Data + Hash,     D: Data + Hash,