Package 'mrgsim.parallel'

Title: Simulate with 'mrgsolve' in Parallel
Description: Simulation from an 'mrgsolve' <https://cran.r-project.org/package=mrgsolve> model using a parallel backend. Input data sets are split (chunked) and simulated in parallel using mclapply() or future_lapply() <https://cran.r-project.org/package=future.apply>.
Authors: Kyle Baron [aut, cre]
Maintainer: Kyle Baron <[email protected]>
License: GPL (>=2)
Version: 0.3.0.9000
Built: 2026-05-08 07:11:46 UTC
Source: https://github.com/kylebaron/mrgsim.parallel

Help Index

Multicore lapply in the background

Description

Multicore lapply in the background

Usage

bg_mclapply(X, FUN, mc.cores = 1, ..., .wait = TRUE, .seed = NULL)

Arguments

X

A list.
FUN

The function to be applied to each element of X.
mc.cores

Passed to parallel::mclapply().
...

Arguments passed to FUN.
.wait

If FALSE, the function returns immediately; if TRUE, then wait until the background job is finished.
.seed

A numeric value used to set the seed for the simulation; this is the only way to control the random number generation for your simulation.

Value

A list of output data.

Examples

ans <- bg_mclapply(seq(10), sqrt, mc.cores = 2)

Run mrgsim in the background

Description

This function uses callr::r_bg() to simulate a dataset in the background, optionally in parallel and optionally saving the results directly to disk in fst, arrow or rds format. Parallelization can be mediated by the parallel package on unix or macos or future on any os.

Usage

bg_mrgsim_d(
  mod,
  data,
  nchunk = 1,
  ...,
  .locker = NULL,
  .tag = NULL,
  .format = c("fst", "feather", "parquet", "rds"),
  .wait = TRUE,
  .seed = FALSE,
  .cores = 1,
  .plan = NULL
)

Arguments

mod

A model object.
data

Data set to simulate; see mrgsolve::data_set().
nchunk

Number of chunks in which to split the data set; chunking will be based on the ID column, which is required in data.
...

Arguments passed to mrgsolve::mrgsim().
.locker

A directory for saving simulated data; use this to collect results from several different runs in a single folder.
.tag

A name to use for the current run; results are saved under .tag in .locker folder.
.format

The output format for saving simulations; using format fst will allow saved results to be read with fst::read_fst(); using format arrow will allow saved results to be read with arrow::open_dataset() with format = "feather" or format = "parquet"; note that fst is installed with mrgsim.parallel but arrow may need explicit installation.
.wait

If FALSE, the function returns immediately; if TRUE, then wait until the background job is finished.
.seed

A numeric value used to set the seed for the simulation; this is the only way to control the random number generation for your simulation.
.cores

The number of cores to parallelize across; pass 1 to run the simulation sequentially.
.plan

The name of a future::plan() strategy; if passed, the parallelization will be handled by the future package.

Details

bg_mrgsim_d() returns a processx::process object (follow that link to see a list of methods). You will have to call process$get_result() to retrieve the result. When an output .locker is not specified, simulated data are returned; when an output .locker is specified, the path to the fst file on disk is returned. The fst files should be read with fst::read_fst(). When the results are not saved to .locker, you will get a single data frame when nchunk is 1 or a list of data frames when nchunk is greater than 1. It is safest to call dplyr::bind_rows() or something equivalent on the result if you are expecting data frame.

Value

An r_process object; see callr::r_bg(). Call process$get_result() to get the actual result (see details). If a .locker path is supplied, the simulated data is saved to disk and a list of file names is returned.

See Also

future_mrgsim_d(), internalize_fst(), list_fst(), head_fst(), setup_locker()

Examples

mod <- mrgsolve::house(delta = 24, end = 168)
data <- mrgsolve::expand.ev(
  amt = c(100, 300, 450), 
  ID = 1:100, 
  ii = 24, 
  addl = 6
)
data <- dplyr::mutate(data, dose = amt)
process <- bg_mrgsim_d(
  mod, 
  data, 
  carry_out = "dose", 
  outvars = "CP",
  .wait = TRUE
) 
process$get_result()
 
 
ds <- file.path(tempdir(), "sims")
files <- bg_mrgsim_d(
  mod, data, carry_out = "dose", 
  .wait = TRUE, 
  .locker = ds,
  .format = "fst"
)
files
sims <- internalize_fst(ds)
head(sims)

Chunk a data frame

Description

Use chunk_by_id to split up a data set by the ID column; use chunk_by_row split a data set by rows.

Usage

chunk_by_id(data, nchunk, id_col = "ID", mark = NULL)

chunk_by_cols(data, nchunk, cols, mark = NULL)

chunk_by_row(data, nchunk, mark = NULL)

Arguments

data

A data frame.
nchunk

The number of chunks.
id_col

Character name specifying the column containing the ID for chunking.
mark

When populated as a character label, adds a column to the chunked data frames with that name and with value the integer group number.
cols

A character vector of columns to use for deriving ID to use for chunking.

Value

A list of data frames.

Examples

x <- expand.grid(ID = 1:10, B = rev(1:10))

chunk_by_id(x, nchunk = 3)

chunk_by_row(x, nchunk = 4)

Set or change the file extension on file_stream names

Description

Add or update the file extension for items in a file_stream object. If a file extension exists, it is removed first.

Usage

ext_stream(x, ext)

Arguments

x

A file_stream object.
ext

The new extension.

See Also

format_stream(), locate_stream(), new_stream(), file_stream(), file_set()

Examples

x <- new_stream(3)
x <- ext_stream(x, "feather")
x[[1]]$file

Generate a sequence of file objects

Description

File names have a numbered core that communicates the current file number as well as the total number of files in the set. For example, 02-20 would indicate the second file in a set of 20. Other customizations can be added.

Usage

file_set(n, where = NULL, prefix = NULL, pad = TRUE, sep = "-", ext = "")

Arguments

n

The number of file names to create.
where

An optional output file path.
prefix

A character prefix for the file name.
pad

If TRUE, numbers will be padded with zeros.
sep

Separator character.
ext

A file extension, including the dot.

Value

By default a list length n of lists length 2; each sublist contains the integer file number as i and the file name as file.

See Also

setup_locker()

Examples

x <- file_set(3, where = "foo/bar")
length(x)
x[2]

x <- file_set(25, ext = ".feather")
x[17]

Create a stream of files

Description

Optionally, setup a locker storage space on disk with a specific file format (e.g. fst or feather).

Usage

file_stream(n, locker = NULL, format = NULL, where = NULL, ...)

Arguments

n

The number of file names to generate; must be a single numeric value greater than or equal to 1.
locker

Passed to setup_locker() as dir; important to note that the directory will be unlinked if it exists and is an established locker directory.
format

Passed to format_stream().
where

An optional file path; this is replaced by locker if it is also passed.
...

Additional arguments passed to file_set().

Details

Pass locker to set up locker space for saving outputs; this involves clearing the locker directory (see setup_locker() for details). Passing locker also sets the path for output files. If you want to set up the path for output files without setting up locker space, pass where.

See Also

format_stream(), locate_stream(), ext_stream(), new_stream(), file_set()

Examples

x <- file_stream(3, locker = temp_ds("foo"), format = "fst")
x[[1]]

Check format status of file set item

Description

This can be used to check if a file set item has been assigned an output format (e.g. fst, feather, parquet, qs or rds). If the check returns FALSE it would signal that data should be returned rather than calling write_stream().

Usage

format_is_set(x)

is.stream_format(x)

Arguments

x

An object, usually a file_set_item.

Value

Logical indicating if x inherits from one of the stream format classes. .

Set the format for a stream_file object

Description

The format is set on the file objects inside the list so that the file object can be used to call a write method. See write_stream().

Usage

format_stream(
  x,
  type = c("fst", "feather", "parquet", "qs", "rds"),
  set_ext = TRUE,
  warn = FALSE
)

Arguments

x

A file_stream object.
type

The file format type; if feather or parquet is chosen, then a check will be made to ensure the arrow package is loaded.
set_ext

If TRUE, the existing extension (if it exists) is stripped and a new extension is added based on the value of type.
warn

If TRUE a warning will be issued in case the output format is set but there is no directory path associated with the file spot in x[[1]].

Value

x is returned with a new class attribute reflecting the expected output format (fst, feather (arrow), parquet (arrow), qs or rds).

See Also

format_is_set(), locate_stream(), ext_stream(), new_stream(), file_stream(), file_set()

Examples

fs <- new_stream(2)
fs <- format_stream(fs, "fst")
fs[[1]]

format_is_set(fs[[1]])

Get the head of an fst file set

Description

Get the head of an fst file set

Usage

head_fst(path, n = 5, i = 1)

Arguments

path

The directory to search.
n

Number of rows to show.
i

Which output output chunk to show.

See Also

get_fst(), list_fst()

Get the contents of an fst file set

Description

Get the contents of an fst file set

Usage

internalize_fst(path, .as_list = FALSE, ...)

get_fst(path, .as_list = FALSE, ...)

Arguments

path

The directory to search.
.as_list

Should the results be returned as a list (TRUE) or a tibble (FALSE).
...

Not used.

See Also

list_fst(), head_fst()

Check if a directory is dedicated locker space

Description

Check if a directory is dedicated locker space

Usage

is_locker_dir(where)

Arguments

where

The locker location.

Check if an object is a file_set_item

Description

Check if an object is a file_set_item

Usage

is.file_set_item(x)

Arguments

x

An object.

Value

Logical value indicating if x has the file_set_item attribute set..

Examples

x <- new_stream(2)
is.file_set_item(x[[2]])

Check if an object inherits from file_stream

Description

Check if an object inherits from file_stream

Usage

is.file_stream(x)

Arguments

x

An object.

Value

Logical value indicating if x inherits from file_stream.

Examples

x <- new_stream(2)
is.file_stream(x)

Check if an object inherits from locker_stream

Description

Check if an object inherits from locker_stream

Usage

is.locker_stream(x)

Arguments

x

An object.

Value

Logical value indicating if x inherits from locker_stream.

Examples

x <- new_stream(2, locker = temp_ds("locker-stream-example"))
is.locker_stream(x)

List all output files in a fst file set

Description

Use the function to read all of the .fst files that were saved when bg_mrgsim_d was called and .path was passed along with .format = "fst".

Usage

list_fst(path)

Arguments

path

The (full) directory path to search.

Set or change the directory for file_stream objects

Description

Add or update the directory location for items in a file_stream object. If a directory path already exists, it is removed first.

Usage

locate_stream(x, where, initialize = FALSE)

Arguments

x

A file_stream object.
where

The new location.
initialize

If TRUE, then the where directory is passed to a call to reset_locker().

Details

When initialize is set to TRUE, the locker space is initialized or reset. In order to initialize, where must not exist or it must have been previously set up as locker space. See setup_locker() for details.

See Also

format_stream(), ext_stream(), new_stream(), file_stream(), file_set()

Examples

x <- new_stream(5)
x <- locate_stream(x, file.path(tempdir(), "foo"))
x[[1]]$file

Run mrgsim after trying to load the shared object

Description

Use this function when running mrgsolve while parallelizing on a multisession worker node where the model dll might not be loaded.

Usage

mrgsim_ms(mod, ...)

mrgsim_worker(mod, ...)

Arguments

mod

a model object
...

passed to mrgsolve::mrgsim()

Examples

mrgsim_worker(mrgsolve:::house())

Simulate with 'mrgsolve' in Parallel

Description

Simulate with 'mrgsolve' in Parallel

Package options

  • mrgsim.parallel.mc.able: if TRUE, multicore will be used if appropriate.

Create a stream of outputs and inputs

Description

By stream we mean a list that pre-specifies the output file names, replicate numbers and possibly input objects for a simulation. Passing locker initiates a call to setup_locker(), which sets up or resets the output directories.

For the data.frame method, the data are chunked into a list by columns listed in cols. Ideally, this is a singlel column that operates as a unique ID across the data set and is used by chunk_by_id() to form the chunks. Alternatively, cols can be multiple column names which are pasted together to form a unique ID that is used for splitting via chunk_by_cols().

Usage

new_stream(x, ...)

## S3 method for class 'list'
new_stream(x, locker = NULL, format = NULL, ...)

## S3 method for class 'data.frame'
new_stream(x, nchunk, cols = "ID", locker = NULL, format = NULL, ...)

## S3 method for class 'numeric'
new_stream(x, ...)

## S3 method for class 'character'
new_stream(x, ...)

Arguments

x

A list or vector to template the stream; for the numeric method, passing a single number will fill x with a sequence of that length.
...

Additional arguments passed to file_set().
locker

Passed to setup_locker() as dir; important to note that the directory will be unlinked if it exists and is an established locker directory.
format

Passed to format_stream().
nchunk

The number of chunks.
cols

The name(s) of the column(s) specifying unique IDs to use to split the data.frame into chunks; this could be a unique ID or a combination of columns that when pasted together form a unique ID.

Value

A list with the following elements:

  • i the position number

  • file the output file name

  • x the input object.

The list has class file_stream as well as locker_stream (if locker was passed) and a class attribute for the output if format was passed.

See Also

format_stream(), locate_stream(), ext_stream(), file_stream(), file_set()

Examples

x <- new_stream(3)
x[[1]]

new_stream(2, locker = file.path(tempdir(), "foo"))

df <- data.frame(ID = c(1,2,3,4))
x <- new_stream(df, nchunk = 2)
x[[2]]

format_is_set(x[[2]])

x <- new_stream(3, format = "fst")
format_is_set(x[[2]])

Prohibit a locker space from being reset

Description

This function removes the the hidden locker file which designates a directory as a locker. Once the locker is modified this way, it cannot be reset again by calling setup_locker() or new_stream().

Usage

noreset_locker(where)

Arguments

where

The locker location.

Value

A logical value indicating if write ability was successfully revoked.

See Also

setup_locker(), reset_locker(), version_locker()

Simulate a data set in parallel

Description

Use future_mrgsim_d() to simulate with the future package. Use mc_mrgsim_d() to simulate with parallel::mclapply.

Usage

future_mrgsim_d(
  mod,
  data,
  nchunk = 4,
  ...,
  .as_list = FALSE,
  .p = NULL,
  .dry = FALSE,
  .seed = TRUE,
  .parallel = TRUE
)

mc_mrgsim_d(
  mod,
  data,
  nchunk = 4,
  ...,
  .as_list = FALSE,
  .p = NULL,
  .dry = FALSE,
  .seed = NULL,
  .parallel = TRUE
)

fu_mrgsim_d(
  mod,
  data,
  nchunk = 4,
  ...,
  .as_list = FALSE,
  .p = NULL,
  .dry = FALSE,
  .seed = TRUE,
  .parallel = TRUE
)

fu_mrgsim_d0(..., .dry = TRUE)

Arguments

mod

The mrgsolve model object see mrgsolve::mrgmod.
data

Data set to simulate; see mrgsolve::data_set().
nchunk

Number of chunks in which to split the data set; chunking will be based on the ID column, which is required in data.
...

Passed to mrgsolve::mrgsim_d().
.as_list

If TRUE a list is return; otherwise (default) a data frame
.p

Post processing function executed on the worker; arguments should be (1) the simulated output (2) the model object.
.dry

If TRUE neither the simulation nor the post processing will be done.
.seed

Passed to future.apply::future_lapply() as future.seed.
.parallel

if FALSE, the simulation will not be parallelized; this is intended for debugging and testing use only.

Value

A data frame or list of simulated data.

See Also

future_mrgsim_ei()

Examples

mod <- mrgsolve::house()

data <- mrgsolve::expand.ev(amt = seq(10))

out <- future_mrgsim_d(mod, data, nchunk = 2)

Simulate an idata set in parallel

Description

Use future_mrgsim_ei to simulate with the future package. Use mc_mrgsim_ei to simulate with parallel::mclapply.

Usage

future_mrgsim_ei(
  mod,
  events,
  idata,
  nchunk = 4,
  ...,
  .as_list = FALSE,
  .p = NULL,
  .dry = FALSE,
  .seed = TRUE,
  .parallel = TRUE
)

fu_mrgsim_ei(
  mod,
  events,
  idata,
  nchunk = 4,
  ...,
  .as_list = FALSE,
  .p = NULL,
  .dry = FALSE,
  .seed = TRUE,
  .parallel = TRUE
)

fu_mrgsim_ei0(..., .dry = TRUE)

mc_mrgsim_ei(
  mod,
  events,
  idata,
  nchunk = 4,
  ...,
  .as_list = FALSE,
  .p = NULL,
  .dry = FALSE,
  .seed = NULL,
  .parallel = TRUE
)

Arguments

mod

The mrgsolve model object see mrgsolve::mrgmod.
events

An event object from mrgsolve; see mrgsolve::ev().
idata

An idata set of parameters, one per simulation unit (individual); see mrgsolve::idata_set().
nchunk

Number of chunks in which to split the data set; chunking will be based on the ID column, which is required in data.
...

Passed to mrgsolve::mrgsim_d().
.as_list

If TRUE a list is return; otherwise (default) a data frame
.p

Post processing function executed on the worker; arguments should be (1) the simulated output (2) the model object.
.dry

If TRUE neither the simulation nor the post processing will be done.
.seed

Passed to future.apply::future_lapply() as future.seed.
.parallel

if FALSE, the simulation will not be parallelized; this is intended for debugging and testing use only.

Value

A data frame or list of simulated data.

See Also

future_mrgsim_ei

Examples

mod <- mrgsolve::house()

events <- mrgsolve::ev(amt = 100)

idata <- data.frame(CL = runif(10, 0.5, 1.5))

out <- future_mrgsim_ei(mod, events, idata)

Initialize the locker directory

Description

This function is called by setup_locker() to initialize and re-initialize a locker directory. We call it reset_locker because it is expected that the locker space is created once and then repeatedly reset and simulations are run and re-run.

Usage

reset_locker(where, pattern = NULL)

Arguments

where

The full path to the locker.
pattern

A regular expression for finding files to clear from the locker directory.

Details

For the locker space to be initialized, the where directory must not exist; if it exists, there will be an error. It is also an error for where to exist and not contain a particular hidden locker file name that marks the directory as established locker space.

NOTE: when the locker is reset, all contents are cleared according to the files matched by pattern. If any un-matched files exist after clearing the directory, a warning will be issued.

See Also

setup_locker(), noreset_locker(), version_locker()

Set up a data storage locker

Description

A locker is a directory structure where an enclosing folder contains subfolders that in turn contain the results of different simulation runs. When the number of simulation result sets is known, a stream of file names is returned. This function is mainly called by other functions; an exported function and documentation is provided in order to better communicate how the locker works.

Usage

setup_locker(where, tag = locker_tag(where))

Arguments

where

The directory that contains tagged directories of run results.
tag

The name of a folder under where; this directory must not exist the first time the locker is set up and will be deleted and re-created each time it is used to store output from a new simulation run.

Details

where must exist when setting up the locker. The directory tag will be created under where and must not exist except if it had previously been set up using setup_locker. Existing tag directories will have a hidden file in them indicating that they are established simulation output folders.

When recreating the tag directory, it will be unlinked and created new. To not try to set up a locker directory that already contains outputs that need to be preserved. You can call noreset_locker() on that directory to prevent future resets.

Value

The locker location.

See Also

reset_locker(), noreset_locker(), version_locker()

Examples

x <- setup_locker(tempdir(), tag = "my-sims")
x

Create a path to a dataset in tempdir

Description

Create a path to a dataset in tempdir

Usage

temp_ds(tag)

Arguments

tag

The dataset subdirectory.

Version locker contents

Description

Version locker contents

Usage

version_locker(where, version = "save", overwrite = FALSE, noreset = FALSE)

Arguments

where

The locker location.
version

A tag to be appended to where for creating a backup of the locker contents.
overwrite

If TRUE, the new location will be removed with unlink() if it exists.
noreset

If TRUE, noreset_locker() is called on the new version.

Value

A logical value indicating whether or not all files were successfully copied to the backup, invisibly.

See Also

reset_locker(), noreset_locker(), setup_locker()

Examples

locker <- file.path(tempdir(), "version-locker-example")

if(dir.exists(locker)) unlink(locker, recursive = TRUE)

x <- new_stream(1, locker = locker)

cat("test", file = file.path(locker, "1-1"))

dir.exists(locker)

list.files(locker, all.files = TRUE)

y <- version_locker(locker, version = "y")

y

list.files(y, all.files = TRUE)

Writer functions for stream_file objects

Description

This function will write out objects that have been assigned a format with either format_stream() or the format argument to new_stream(). See examples.

Usage

write_stream(x, ...)

## Default S3 method:
write_stream(x, data, ...)

## S3 method for class 'stream_format_fst'
write_stream(x, data, dir = NULL, ...)

## S3 method for class 'stream_format_feather'
write_stream(x, data, dir = NULL, ...)

## S3 method for class 'stream_format_parquet'
write_stream(x, data, dir = NULL, ...)

## S3 method for class 'stream_format_qs'
write_stream(x, data, dir = NULL, ...)

## S3 method for class 'stream_format_rds'
write_stream(x, data, dir = NULL, ...)

Arguments

x

A file_stream object.
...

Not used.
data

An object to write.
dir

An optional directory location to be used if not already in the file spot in x.

Details

The default method always returns FALSE; other methods which get invoked if a format was set will return TRUE. So, the user can always call write_stream() and check the return value: if TRUE, the file was written to disk and the data to not need to be returned; a FALSE return value indicates that no format was set and the data should be returned.

Note the write methods can be invoked directly for a specific format if no format was set (see examples).

Value

A logical value indicating if the output was written or not.

See Also

format_stream(), ext_stream(), locate_stream(), new_stream(), file_stream()

Examples

ds <- temp_ds("example")

fs <- new_stream(2, locker = ds, format = "fst")

data <- data.frame(x = rnorm(10))

x <- lapply(fs, write_stream, data = data)

list.files(ds)

reset_locker(ds)

fs <- format_stream(fs, "rds")

x <- lapply(fs, write_stream, data = data)

list.files(ds)