`R/future_Map.R`

, `R/future_mapply.R`

`future_mapply.Rd`

`future_mapply()`

implements `base::mapply()`

using futures with perfect
replication of results, regardless of future backend used.
Analogously to `mapply()`

, `future_mapply()`

is a multivariate version of
`future_sapply()`

.
It applies `FUN`

to the first elements of each `\ldots`

argument,
the second elements, the third elements, and so on.
Arguments are recycled if necessary.

future_Map( f, ..., future.envir = parent.frame(), future.label = "future_Map-%d" ) future_mapply( FUN, ..., MoreArgs = NULL, SIMPLIFY = TRUE, USE.NAMES = TRUE, future.envir = parent.frame(), future.stdout = TRUE, future.conditions = "condition", future.globals = TRUE, future.packages = NULL, future.seed = FALSE, future.scheduling = 1, future.chunk.size = NULL, future.label = "future_mapply-%d" ) future_.mapply(FUN, dots, MoreArgs, ..., future.label = "future_.mapply-%d")

f | A function of the arity \(k\) if |
---|---|

future.envir | An environment passed as argument |

future.label | If a character string, then each future is assigned
a label |

FUN | A function to apply, found via |

MoreArgs | A list of other arguments to |

SIMPLIFY | A logical or character string; attempt to reduce the
result to a vector, matrix or higher dimensional array; see the simplify
argument of |

USE.NAMES | A logical; use names if the first |

future.stdout | If |

future.conditions | A character string of conditions classes to be
captured and relayed. The default is the same as the |

future.globals | A logical, a character vector, or a named list for
controlling how globals are handled.
For details, see |

future.packages | (optional) a character vector specifying packages to be attached in the R environment evaluating the future. |

future.seed | A logical or an integer (of length one or seven), or
a list of |

future.scheduling | Average number of futures ("chunks") per worker.
If |

future.chunk.size | The average number of elements per future ("chunk").
If |

dots | A list of arguments to vectorize over (vectors or lists of strictly positive length, or all of zero length). |

... | Arguments to vectorize over (vectors or lists of strictly positive length, or all of zero length). |

`future_Map()`

is a simple wrapper to `future_mapply()`

which does not
attempt to simplify the result.
See `base::Map()`

for details.

`future_mapply()`

returns a list, or for `SIMPLIFY = TRUE`

, a vector,
array or list. See `base::mapply()`

for details.

`future_.mapply()`

returns a list. See `base::.mapply()`

for details.

Note that `base::.mapply()`

, which `future_.mapply()`

is modeled after
is listed as an "internal" function in R despite being exported.

The implementations of `future_Map()`

is adopted from the source code
of the corresponding base R function `Map()`

, which is licensed under
GPL (>= 2) with 'The R Core Team' as the copyright holder.

## --------------------------------------------------------- ## mapply() ## --------------------------------------------------------- y0 <- mapply(rep, 1:4, 4:1) y1 <- future_mapply(rep, 1:4, 4:1) stopifnot(identical(y1, y0)) y0 <- mapply(rep, times = 1:4, x = 4:1) y1 <- future_mapply(rep, times = 1:4, x = 4:1) stopifnot(identical(y1, y0)) y0 <- mapply(rep, times = 1:4, MoreArgs = list(x = 42)) y1 <- future_mapply(rep, times = 1:4, MoreArgs = list(x = 42)) stopifnot(identical(y1, y0)) y0 <- mapply(function(x, y) seq_len(x) + y, c(a = 1, b = 2, c = 3), # names from first c(A = 10, B = 0, C = -10)) y1 <- future_mapply(function(x, y) seq_len(x) + y, c(a = 1, b = 2, c = 3), # names from first c(A = 10, B = 0, C = -10)) stopifnot(identical(y1, y0)) word <- function(C, k) paste(rep.int(C, k), collapse = "") y0 <- mapply(word, LETTERS[1:6], 6:1, SIMPLIFY = FALSE) y1 <- future_mapply(word, LETTERS[1:6], 6:1, SIMPLIFY = FALSE) stopifnot(identical(y1, y0)) ## --------------------------------------------------------- ## Parallel Random Number Generation ## --------------------------------------------------------- # \donttest{ ## Regardless of the future plan, the number of workers, and ## where they are, the random numbers produced are identical plan(multisession) set.seed(0xBEEF) y1 <- future_mapply(stats::runif, n = 1:4, max = 2:5, MoreArgs = list(min = 1), future.seed = TRUE) print(y1)#> [[1]] #> [1] 1.094084 #> #> [[2]] #> [1] 1.133518 1.415726 #> #> [[3]] #> [1] 3.992017 3.395174 3.470525 #> #> [[4]] #> [1] 2.693828 1.588631 2.708467 4.411477 #>plan(sequential) set.seed(0xBEEF) y2 <- future_mapply(stats::runif, n = 1:4, max = 2:5, MoreArgs = list(min = 1), future.seed = TRUE) print(y2)#> [[1]] #> [1] 1.094084 #> #> [[2]] #> [1] 1.133518 1.415726 #> #> [[3]] #> [1] 3.992017 3.395174 3.470525 #> #> [[4]] #> [1] 2.693828 1.588631 2.708467 4.411477 #>