The registerDoSEQ function is used to explicitly register a sequential parallel backend with the foreach package. This will prevent a warning message from being issued if the %dopar% function is called and no parallel backend has been registered.
The setDoSeq function is used to register a sequential backend with the foreach package. This isn't normally executed by the user. Instead, packages that provide a sequential backend provide a function named registerDoSeq that calls setDoSeq using the appropriate arguments.
getDoParWorkers
(Package: foreach) :
Functions Providing Information on the doPar Backend
The getDoParWorkers function returns the number of execution workers there are in the currently registered doPar backend. It can be useful when determining how to split up the work to be executed in parallel. A 1 is returned by default.
These functions are used to write parallel backends for the foreach package. They should not be used from normal scripts or packages that use the foreach package.
The foreach package provides a new looping construct for executing R code repeatedly. The main reason for using the foreach package is that it supports parallel execution. The foreach package can be used with a variety of different parallel computing systems, include NetWorkSpaces and snow. In addition, foreach can be used with iterators, which allows the data to specified in a very flexible way.
The setDoPar function is used to register a parallel backend with the foreach package. This isn't normally executed by the user. Instead, packages that provide a parallel backend provide a function named registerDoPar that calls setDoPar using the appropriate arguments.
%do% and %dopar% are binary operators that operate on a foreach object and an R expression. The expression, ex, is evaluated multiple times in an environment that is created by the foreach object, and that environment is modified for each evaluation as specified by the foreach object. %do% evaluates the expression sequentially, while %dopar% evalutes it in parallel. The results of evaluating ex are returned as a list by default, but this can be modified by means of the .combine argument.
● Data Source:
CranContrib
● Keywords: utilities
● Alias: %:%, %do%, %dopar%, foreach, times, when
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getDoSeqWorkers
(Package: foreach) :
Functions Providing Information on the doSeq Backend
The getDoSeqWorkers function returns the number of execution workers there are in the currently registered doSeq backend. A 1 is returned by default.
providing 
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