Jobs go in. Results come out.
globals |
A named list of variables that all <job>$expr s will have
access to. Alternatively, an object that can be coerced to a named
list with as.list() , e.g. named vector, data.frame, or environment.
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packages |
Character vector of package names to load on
workers .
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namespace |
The name of a package to attach to the
worker's environment.
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init |
A call or R expression wrapped in curly braces to evaluate on
each worker just once, immediately after start-up.
Will have access to variables defined by globals and assets from
packages and namespace . Returned value is ignored.
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max_cpus |
Total number of CPU cores that can be reserved by all
running jobs (sum(<job>$cpus) ). Does not enforce
limits on actual CPU utilization.
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workers |
How many background worker processes to
start. Set to more than max_cpus to enable standby
workers to quickly swap out with
workers that need to restart.
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timeout |
A named numeric vector indicating the maximum number of
seconds allowed for each state the job passes through,
or 'total' to apply a single timeout from 'submitted' to 'done'. Can
also limit the 'starting' state for workers . A
function (job) can be used in place of a number.
Example: timeout = c(total = 2.5, running = 1) .
See vignette('stops') .
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hooks |
A named list of functions to run when the job
state changes, of the form
hooks = list(created = function (worker) {...}) . Or a
function (job) that returns the same. Names of
worker hooks are typically 'created' ,
'submitted' , 'queued' , 'dispatched' , 'starting' , 'running' ,
'done' , or '*' (duplicates okay). See vignette('hooks') .
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reformat |
Set reformat = function (job) to define what
<job>$result should return. The default, reformat = NULL passes
<job>$output to <job>$result unchanged.
See vignette('results') .
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signal |
Should calling <job>$result signal on condition objects?
When FALSE , <job>$result will return the object without
taking additional action. Setting to TRUE or a character vector of
condition classes, e.g. c('interrupt', 'error', 'warning') , will
cause the equivalent of stop(<condition>) to be called when those
conditions are produced. Alternatively, a function (job) that
returns TRUE or FALSE . See vignette('results') .
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cpus |
The default number of CPU cores per job . Or a
function (job) that returns the number of CPU cores to reserve for
a given job . Used to limit the number of
jobs running simultaneously to respect
<jobqueue>$max_cpus . Does not prevent a job from
using more CPUs than reserved.
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stop_id |
If an existing job in the
jobqueue has the same stop_id , that
job will be stopped and return an 'interrupt'
condition object as its result. stop_id can also be a
function (job) that returns the stop_id to assign to a given
job . A stop_id of NULL disables this feature.
See vignette('stops') .
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copy_id |
If an existing job in the
jobqueue has the same copy_id , the newly
submitted job will become a "proxy" for that earlier
job , returning whatever result the earlier
job returns. copy_id can also be a function (job)
that returns the copy_id to assign to a given job .
A copy_id of NULL disables this feature. See vignette('stops') .
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