Trait differential_dataflow::operators::iterate::Iterate

pub trait Iterate<G: Scope, D: Data, R: Semigroup> {
    // Required method
    fn iterate<F>(&self, logic: F) -> Collection<G, D, R>
       where G::Timestamp: Lattice,
             for<'a> F: FnOnce(&Collection<Iterative<'a, G, u64>, D, R>) -> Collection<Iterative<'a, G, u64>, D, R>;
}

An extension trait for the iterate method.

Required Methods

fn iterate<F>(&self, logic: F) -> Collection<G, D, R>

where G::Timestamp: Lattice, for<'a> F: FnOnce(&Collection<Iterative<'a, G, u64>, D, R>) -> Collection<Iterative<'a, G, u64>, D, R>,

Iteratively apply logic to the source collection until convergence.

Importantly, this method does not automatically consolidate results. It may be important to conclude with consolidate() to ensure that logically empty collections that contain cancelling records do not result in non-termination. Operators like reduce, distinct, and count also perform consolidation, and are safe to conclude with.

Examples

use differential_dataflow::input::Input;
use differential_dataflow::operators::Iterate;

::timely::example(|scope| {

    scope.new_collection_from(1 .. 10u32).1
         .iterate(|values| {
             values.map(|x| if x % 2 == 0 { x/2 } else { x })
                   .consolidate()
         });
});

Object Safety

This trait is not object safe.

Implementors

impl<G: Scope, D: Ord + Data + Debug, R: Abelian> Iterate<G, D, R> for Collection<G, D, R>

impl<G: Scope, D: Ord + Data + Debug, R: Semigroup> Iterate<G, D, R> for G