parallel

Documentation

Overview

Package parallel provides primitives for running tasks in parallel.

Index

• func Do(parallelism int, n int, f func(i int))
• func DoContext(ctx context.Context, parallelism int, n int, ...) error
• func Map[T any, U any](parallelism int, in []T, f func(in T) U) []U
• func MapContext[T any, U any](ctx context.Context, parallelism int, in []T, ...) ([]U, error)
• func MapIterator[T any, U any](iter iterator.Iterator[T], parallelism int, bufferSize int, f func(T) U) iterator.Iterator[U]
• func MapStream[T any, U any](ctx context.Context, s stream.Stream[T], parallelism int, bufferSize int, ...) stream.Stream[U]

Functions

func Do

func Do(
	parallelism int,
	n int,
	f func(i int),
)

Do calls f from parallelism goroutines n times, providing each invocation a unique i in [0, n).

If parallelism <= 0, uses GOMAXPROCS instead.

func DoContext

func DoContext(
	ctx context.Context,
	parallelism int,
	n int,
	f func(ctx context.Context, i int) error,
) error

DoContext calls f from parallelism goroutines n times, providing each invocation a unique i in [0, n).

If any call to f returns an error the context passed to invocations of f is cancelled, no further calls to f are made, and Do returns the first error encountered.

If parallelism <= 0, uses GOMAXPROCS instead.

func Map

func Map[T any, U any](
	parallelism int,
	in []T,
	f func(in T) U,
) []U

Map uses parallelism goroutines to call f once for each element of in. out[i] is the result of f for in[i].

If parallelism <= 0, uses GOMAXPROCS instead.

func MapContext

func MapContext[T any, U any](
	ctx context.Context,
	parallelism int,
	in []T,
	f func(ctx context.Context, in T) (U, error),
) ([]U, error)

MapContext uses parallelism goroutines to call f once for each element of in. out[i] is the result of f for in[i].

If any call to f returns an error the context passed to invocations of f is cancelled, no further calls to f are made, and Map returns the first error encountered.

If parallelism <= 0, uses GOMAXPROCS instead.

func MapIterator

func MapIterator[T any, U any](
	iter iterator.Iterator[T],
	parallelism int,
	bufferSize int,
	f func(T) U,
) iterator.Iterator[U]

MapIterator uses parallelism goroutines to call f once for each element yielded by iter. The returned iterator returns these results in the same order that iter yielded them in.

This iterator, in contrast with most, must be consumed completely or it will leak the goroutines.

If parallelism <= 0, uses GOMAXPROCS instead.

bufferSize is the size of the work buffer. A larger buffer uses more memory but gives better throughput in the face of larger variance in the processing time for f.

func MapStream

func MapStream[T any, U any](
	ctx context.Context,
	s stream.Stream[T],
	parallelism int,
	bufferSize int,
	f func(context.Context, T) (U, error),
) stream.Stream[U]

MapStream uses parallelism goroutines to call f once for each element yielded by s. The returned stream returns these results in the same order that s yielded them in.

If any call to f returns an error the context passed to invocations of f is cancelled, no further calls to f are made, and the returned stream's Next returns the first error encountered.

If parallelism <= 0, uses GOMAXPROCS instead.

bufferSize is the size of the work buffer. A larger buffer uses more memory but gives better throughput in the face of larger variance in the processing time for f.