This vignette provides a short example on how to use the R package
bhmbasket in a high performance computing (HPC) environment
using the R packages doFuture and
future.batchtools.
The code below provides an example for specifying a parallel backend
using the future framework with the SLURM job scheduler. Kindly see the
documentation of the R packages doFuture and
future.batchtools for further options. This code is to be
run on the master node.
## Adapt the SLURM template to requirements
job_time <- 1 # time for job in hours
n_workers <- 24 # number of worker nodes
n_cpus <- 16 # number of cpus per worker node
gb_memory <- 2 # memory [GB] per cpu
slurm <- tweak(batchtools_slurm,
template = system.file('templates/slurm-simple.tmpl',
package = 'batchtools'),
workers = n_workers,
resources = list(
walltime = 60 * 60 * job_time,
ncpus = n_cpus,
memory = 1000 * gb_memory))
## Register the parallel backend
registerDoFuture()
## Specify how the futures should be resolved
plan(list(slurm, multisession))The R package bhmbasket makes use of the foreach
framework and runs with every applicable parallel backend. With a
parallel backend registered as shown above and running the code on the
master node, the job scheduler will automatically distribute the jobs to
the worker nodes via plan(slurm), and with the nested
parallelization built into performAnalyses(), each worker
node makes use of its CPUs via plan(multisession).
Below is some example code, which was taken from the examples section
of ?bhmbasket::getEstimates. Due to the foreach framework,
no adjustments to the code are necessary. Kindly note that running this
small example on a HPC environment will most likely not result in a
performance improvement.
scenarios_list <- simulateScenarios(
n_subjects_list = list(c(10, 20, 30)),
response_rates_list = list(c(0.1, 0.2, 3)),
n_trials = 10)
analyses_list <- performAnalyses(
scenario_list = scenarios_list,
target_rates = c(0.1, 0.1, 0.1),
calc_differences = matrix(c(3, 2, 2, 1), ncol = 2),
n_mcmc_iterations = 100)
getEstimates(analyses_list)