Trait differential_dataflow::lattice::Lattice
source · pub trait Lattice: PartialOrder {
// Required methods
fn join(&self, other: &Self) -> Self;
fn meet(&self, other: &Self) -> Self;
// Provided methods
fn join_assign(&mut self, other: &Self)
where Self: Sized { ... }
fn meet_assign(&mut self, other: &Self)
where Self: Sized { ... }
fn advance_by(&mut self, frontier: AntichainRef<'_, Self>)
where Self: Sized { ... }
}Expand description
A bounded partially ordered type supporting joins and meets.
Required Methods§
Provided Methods§
sourcefn join_assign(&mut self, other: &Self)where
Self: Sized,
fn join_assign(&mut self, other: &Self)where
Self: Sized,
Updates self to the smallest element greater than or equal to both arguments.
§Examples
let mut time1 = Product::new(3, 7);
let time2 = Product::new(4, 6);
time1.join_assign(&time2);
assert_eq!(time1, Product::new(4, 7));sourcefn meet_assign(&mut self, other: &Self)where
Self: Sized,
fn meet_assign(&mut self, other: &Self)where
Self: Sized,
Updates self to the largest element less than or equal to both arguments.
§Examples
let mut time1 = Product::new(3, 7);
let time2 = Product::new(4, 6);
time1.meet_assign(&time2);
assert_eq!(time1, Product::new(3, 6));sourcefn advance_by(&mut self, frontier: AntichainRef<'_, Self>)where
Self: Sized,
fn advance_by(&mut self, frontier: AntichainRef<'_, Self>)where
Self: Sized,
Advances self to the largest time indistinguishable under frontier.
This method produces the “largest” lattice element with the property that for every
lattice element greater than some element of frontier, both the result and self
compare identically to the lattice element. The result is the “largest” element in
the sense that any other element with the same property (compares identically to times
greater or equal to frontier) must be less or equal to the result.
When provided an empty frontier self is not modified.
§Examples
use timely::progress::frontier::{Antichain, AntichainRef};
let time = Product::new(3, 7);
let mut advanced = Product::new(3, 7);
let frontier = Antichain::from(vec![Product::new(4, 8), Product::new(5, 3)]);
advanced.advance_by(frontier.borrow());
// `time` and `advanced` are indistinguishable to elements >= an element of `frontier`
for i in 0 .. 10 {
for j in 0 .. 10 {
let test = Product::new(i, j);
// for `test` in the future of `frontier` ..
if frontier.less_equal(&test) {
assert_eq!(time.less_equal(&test), advanced.less_equal(&test));
}
}
}
assert_eq!(advanced, Product::new(4, 7));Object Safety§
This trait is not object safe.