doRedis (version 2.0.0)

registerDoRedis: Register the Redis back end for foreach.

Description

The doRedis package imlpements a simple but flexible parallel back end for foreach that uses Redis for inter-process communication. The work queue name specifies the base name of a small set of Redis keys that the master and worker processes use to exchange data.

Usage

registerDoRedis(
  queue,
  host = "localhost",
  port = 6379,
  password,
  ftinterval = 30,
  chunkSize = 1,
  progress = FALSE,
  ...
)

Arguments

queue

A work queue name

host

The Redis server host name or IP address

port

The Redis server port number

password

An optional Redis database password

ftinterval

Default fault tolerance interval in seconds

chunkSize

Default iteration granularity, see setChunkSize

progress

(logical) Show progress bar for computations?

...

Optional arguments passed to redisConnect

Value

NULL is invisibly returned.

Details

Back-end worker R processes advertise their availablility for work with the redisWorker function.

The doRedis parallel back end tolerates faults among the worker processes and automatically resubmits failed tasks. It is also portable and supports heterogeneous sets of workers, even across operative systems. The back end supports dynamic pools of worker processes. New workers may be added to work queues at any time and can be used by running foreach computations.

See Also

foreach, doRedis-package, setChunkSize, removeQueue

Examples

# NOT RUN {
## The example assumes that a Redis server is running on the local host
## and standard port.

## 1. Open one or more 'worker' R sessions and run:
require('doRedis')
redisWorker('jobs')

## 2. Open another R session acting as a 'master' and run this simple
##    sampling approximation of pi:
require('doRedis')
registerDoRedis('jobs')
foreach(j=1:10, .combine=sum, .multicombine=TRUE) \<!-- %dopar\\% -->
        4 * sum((runif(1000000) ^ 2 + runif(1000000) ^ 2) < 1) / 10000000
removeQueue('jobs')
# }
# NOT RUN {
# }