Command line

Sometimes, the analyst wants to run an R script from the shell and override a few configuration values at runtime, without editing YAML files. They may also want a multi-run call that executes the same script over a grid of configuration parameters.

This workflow can be achieved using Rscript and the hydraR::main() function.

Minimal example

When you only need one run with default parameters, a minimal config and a single Rscript call keep things simple and reproducible.

The full minimal.yml used in this example is:

author:
  given: Vincent
  family: Arel-Bundock
numeric: 2

The example.R script executed by Rscript is:

#!/usr/bin/env Rscript

square <- function(cfg) {
    x <- cfg$numeric
    out <- sprintf("Input=%s -> Square=%s", x, x^2)
    print(out)
}

hydraR::main(
    square,
    config_path = "/path/to/config/",
    config_name = "minimal"
)

Run the script once with no command-line overrides:

Rscript example.R

The printed output is:

[1] "Input=2 -> Square=4"

Config override

When one script needs to run against different config folders or file names, you can switch both from the command line without editing the script itself.

Rscript example.R --config-path config_alt/ --config-name minimal

Parameter override

A common workflow is to keep a stable base config and override just one value from the shell for quick experiments.

Using the same minimal config as before, we can do a single parameter override:

Rscript example.R 'numeric=3'

The printed output is:

[1] "Input=3 -> Square=9"

Multi-parameter sweep

When you want to evaluate multiple values in one command, multi-run sweeps avoid manual repetition and keep runs consistent.

Run a sweep with -m across three values, separated by commas:

Rscript example.R -m 'numeric=2,3,4'

The printed output is:

[1] "Input=2 -> Square=4"
[1] "Input=3 -> Square=9"
[1] "Input=4 -> Square=16"

Global options

If many functions share the same config, setting hydraR.main.* options lets you avoid repeating config_path and config_name on every call.

The example.R script executed by Rscript is:

#!/usr/bin/env Rscript

options(
    hydraR.main.config_path = "/path/to/config/",
    hydraR.main.config_name = "minimal"
)

square <- function(cfg) {
    x <- cfg$numeric
    out <- sprintf("Input=%s -> Square=%s", x, x^2)
    print(out)
}

cube <- function(cfg) {
    x <- cfg$numeric
    out <- sprintf("Input=%s -> Square=%s", x, x^3)
    print(out)
}

hydraR::main(square)
hydraR::main(cube)