R: Get set of available workers

availableWorkers {future} | R Documentation

## Get set of available workers

### Description

Get set of available workers

### Usage

    availableWorkers(methods = getOption("future.availableWorkers.methods",
      c("mc.cores", "_R_CHECK_LIMIT_CORES_", "PBS", "SGE", "Slurm", "system",
      "fallback")), na.rm = TRUE, default = "localhost", which = c("auto",
      "min", "max", "all"))

### Arguments

`methods` | A character vector specifying how to infer the number of available cores.
`na.rm` | If TRUE, only non-missing settings are considered/returned.
`default` | The default set of workers.
`which` | A character specifying which set / sets to return. If `"auto"`, the first non-empty set found. If `"min"`, the minimum value is returned. If `"max"`, the maximum value is returned (be careful!) If `"all"`, all values are returned.

### Details

The default set of workers for each method is `rep("localhost", times = availableCores(method))`, which means that each will at least use as many parallel workers on the current machine that `availableCores()` allows for that method.

In addition, the following settings ("methods") are also acknowledged:

- `"PBS"` - Query TORQUE/PBS environment variable PBS_NODEFILE. If this is set and specifies an existing file, then the set of workers is read from that file, where one worker (node) is given per line. An example of a job submission that results in this is `qsub -l nodes = 4:ppn = 2`, which requests four nodes each with two cores.

- `"SGE"` - Query Sun/Oracle Grid Engine (SGE) environment variable PE_HOSTFILE. An example of a job submission that results in this is `qsub -pe mpi 8` (or `qsub -pe ompi 8`), which requests eight cores on a any number of machines.

### Value

Return a character vector of workers, which typically consists of names of machines / compute nodes, but may also be IP numbers.

### See Also

To get the number of available workers on the current machine, see `availableCores()`.

[Package future version 1.9.0 Index]