[−][src]Trait timely::dataflow::scopes::Scope
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
fn name(&self) -> String
A useful name describing the scope.
fn addr(&self) -> Vec<usize>
A sequence of scope identifiers describing the path from the worker root to this scope.
fn add_edge(&self, source: Source, target: Target)
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.
fn allocate_operator_index(&mut self) -> usize
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.
fn add_operator_with_indices(
&mut self,
operator: Box<dyn Operate<Self::Timestamp>>,
local: usize,
global: usize
)
&mut self,
operator: Box<dyn Operate<Self::Timestamp>>,
local: usize,
global: usize
)
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.
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,
T: Timestamp + Refines<Self::Timestamp>,
F: FnOnce(&mut Child<Self, T>) -> R,
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
fn add_operator(&mut self, operator: Box<dyn Operate<Self::Timestamp>>) -> usize
Adds a child Operate
to the builder's scope. Returns the new child's index.
fn add_operator_with_index(
&mut self,
operator: Box<dyn Operate<Self::Timestamp>>,
index: usize
)
&mut self,
operator: Box<dyn Operate<Self::Timestamp>>,
index: usize
)
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.
fn iterative<T, R, F>(&mut self, func: F) -> R where
T: Timestamp,
F: FnOnce(&mut Child<Self, Product<Self::Timestamp, T>>) -> R,
T: Timestamp,
F: FnOnce(&mut Child<Self, Product<Self::Timestamp, T>>) -> R,
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 }); });
fn region<R, F>(&mut self, func: F) -> R where
F: FnOnce(&mut Child<Self, Self::Timestamp>) -> R,
F: FnOnce(&mut Child<Self, Self::Timestamp>) -> R,
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 }); });
Implementors
impl<'a, G, T> Scope for Child<'a, G, T> where
G: ScopeParent,
T: Timestamp + Refines<G::Timestamp>,
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G: ScopeParent,
T: Timestamp + Refines<G::Timestamp>,
fn name(&self) -> String
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fn addr(&self) -> Vec<usize>
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fn add_edge(&self, source: Source, target: Target)
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fn add_operator_with_indices(
&mut self,
operator: Box<dyn Operate<Self::Timestamp>>,
local: usize,
global: usize
)
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&mut self,
operator: Box<dyn Operate<Self::Timestamp>>,
local: usize,
global: usize
)
fn allocate_operator_index(&mut self) -> usize
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fn scoped<T2, R, F>(&mut self, name: &str, func: F) -> R where
T2: Timestamp + Refines<T>,
F: FnOnce(&mut Child<Self, T2>) -> R,
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T2: Timestamp + Refines<T>,
F: FnOnce(&mut Child<Self, T2>) -> R,
fn add_operator(&mut self, operator: Box<dyn Operate<Self::Timestamp>>) -> usize
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fn add_operator_with_index(
&mut self,
operator: Box<dyn Operate<Self::Timestamp>>,
index: usize
)
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&mut self,
operator: Box<dyn Operate<Self::Timestamp>>,
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,
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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,
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F: FnOnce(&mut Child<Self, Self::Timestamp>) -> R,