Function half_join

pub fn half_join<G, K, V, R, Tr, FF, CF, DOut, S>(
    stream: &VecCollection<G, (K, V, G::Timestamp), R>,
    arrangement: Arranged<G, Tr>,
    frontier_func: FF,
    comparison: CF,
    output_func: S,
) -> VecCollection<G, (DOut, G::Timestamp), <R as Mul<Tr::Diff>>::Output>
where
    G: Scope<Timestamp = Tr::Time>,
    K: Hashable + ExchangeData,
    V: ExchangeData,
    R: ExchangeData + Monoid + Mul<Tr::Diff, Output: Semigroup>,
    Tr: TraceReader<KeyOwn = K, Time: Hash> + Clone + 'static,
    FF: Fn(&G::Timestamp, &mut Antichain<G::Timestamp>) + 'static,
    CF: Fn(Tr::TimeGat<'_>, &G::Timestamp) -> bool + 'static,
    DOut: Clone + 'static,
    S: FnMut(&K, &V, Tr::Val<'_>) -> DOut + 'static,

A binary equijoin that responds to updates on only its first input.

This operator responds to inputs of the form

((key, val1, time1), initial_time, diff1)

where initial_time is less or equal to time1, and produces as output

((output_func(key, val1, val2), lub(time1, time2)), initial_time, diff1 * diff2)

for each ((key, val2), time2, diff2) present in arrangement, where time2 is less than initial_time UNDER THE TOTAL ORDER ON TIMES. This last constraint is important to ensure that we correctly produce all pairs of output updates across multiple half_join operators.

Notice that the time is hoisted up into data. The expectation is that once out of the “delta flow region”, the updates will be delayd to the times specified in the payloads.