Trait timely_util::Scope

source ·
pub trait Scope: ScopeParent {
    fn name(&self) -> String;
    fn addr(&self) -> Vec<usize, Global>;
    fn add_edge(&self, source: Source, target: Target);
    fn allocate_operator_index(&mut self) -> usize;
    fn add_operator_with_indices(
        &mut self,
        operator: Box<dyn Operate<Self::Timestamp> + 'static, Global>,
        local: usize,
        global: usize
    ); fn scoped<T, R, F>(&mut self, name: &str, func: F) -> R
    where
        T: Timestamp + Refines<Self::Timestamp>,
        F: FnOnce(&mut Child<'_, Self, T>) -> R
; fn add_operator(
        &mut self,
        operator: Box<dyn Operate<Self::Timestamp> + 'static, Global>
    ) -> usize { ... } fn add_operator_with_index(
        &mut self,
        operator: Box<dyn Operate<Self::Timestamp> + 'static, Global>,
        index: usize
    ) { ... } fn iterative<T, R, F>(&mut self, func: F) -> R
    where
        T: Timestamp,
        F: FnOnce(&mut Child<'_, Self, Product<Self::Timestamp, T>>) -> R
, { ... } fn region<R, F>(&mut self, func: F) -> R
    where
        F: FnOnce(&mut Child<'_, Self, Self::Timestamp>) -> R
, { ... } fn region_named<R, F>(&mut self, name: &str, func: F) -> R
    where
        F: FnOnce(&mut Child<'_, Self, Self::Timestamp>) -> R
, { ... } }
Expand description

The fundamental operations required to add and connect operators in a timely dataflow graph.

Importantly, this is often a shared object, backed by a Rc<RefCell<>> wrapper. Each method takes a shared reference, but can be thought of as first calling .clone() and then calling the method. Each method does not hold the RefCell’s borrow, and should prevent accidental panics.

Required Methods§

A useful name describing the scope.

A sequence of scope identifiers describing the path from the worker root to this scope.

Connects a source of data with a target of the data. This only links the two for the purposes of tracking progress, rather than effect any data movement itself.

Allocates a new scope-local operator index.

This method is meant for use with add_operator_with_index, which accepts a scope-local operator index allocated with this method. This method does cause the scope to expect that an operator will be added, and it is an error not to eventually add such an operator.

Adds a child Operate to the builder’s scope using supplied indices.

The two indices are the scope-local operator index, and a worker-unique index used for e.g. logging.

Creates a dataflow subgraph.

This method allows the user to create a nested scope with any timestamp that “refines” the enclosing timestamp (informally: extends it in a reversible way).

This is most commonly used to create new iterative contexts, and the provided method iterative for this task demonstrates the use of this method.

Examples
use timely::dataflow::Scope;
use timely::dataflow::operators::{Input, Enter, Leave};
use timely::order::Product;

timely::execute_from_args(std::env::args(), |worker| {
    // must specify types as nothing else drives inference.
    let input = worker.dataflow::<u64,_,_>(|child1| {
        let (input, stream) = child1.new_input::<String>();
        let output = child1.scoped::<Product<u64,u32>,_,_>("ScopeName", |child2| {
            stream.enter(child2).leave()
        });
        input
    });
});

Provided Methods§

Adds a child Operate to the builder’s scope. Returns the new child’s index.

Adds a child Operate to the builder’s scope using a supplied index.

This is used internally when there is a gap between allocate a child identifier and adding the child, as happens in subgraph creation.

Creates a iterative dataflow subgraph.

This method is a specialization of scoped which uses the Product timestamp combinator, suitable for iterative computations in which iterative development at some time cannot influence prior iterations at a future time.

Examples
use timely::dataflow::Scope;
use timely::dataflow::operators::{Input, Enter, Leave};

timely::execute_from_args(std::env::args(), |worker| {
    // must specify types as nothing else drives inference.
    let input = worker.dataflow::<u64,_,_>(|child1| {
        let (input, stream) = child1.new_input::<String>();
        let output = child1.iterative::<u32,_,_>(|child2| {
            stream.enter(child2).leave()
        });
        input
    });
});

Creates a dataflow region with the same timestamp.

This method is a specialization of scoped which uses the same timestamp as the containing scope. It is used mainly to group regions of a dataflow computation, and provides some computational benefits by abstracting the specifics of the region.

Examples
use timely::dataflow::Scope;
use timely::dataflow::operators::{Input, Enter, Leave};

timely::execute_from_args(std::env::args(), |worker| {
    // must specify types as nothing else drives inference.
    let input = worker.dataflow::<u64,_,_>(|child1| {
        let (input, stream) = child1.new_input::<String>();
        let output = child1.region(|child2| {
            stream.enter(child2).leave()
        });
        input
    });
});

Creates a dataflow region with the same timestamp.

This method is a specialization of scoped which uses the same timestamp as the containing scope. It is used mainly to group regions of a dataflow computation, and provides some computational benefits by abstracting the specifics of the region.

This variant allows you to specify a name for the region, which can be read out in the timely logging streams.

Examples
use timely::dataflow::Scope;
use timely::dataflow::operators::{Input, Enter, Leave};

timely::execute_from_args(std::env::args(), |worker| {
    // must specify types as nothing else drives inference.
    let input = worker.dataflow::<u64,_,_>(|child1| {
        let (input, stream) = child1.new_input::<String>();
        let output = child1.region_named("region", |child2| {
            stream.enter(child2).leave()
        });
        input
    });
});

Implementors§