drake (version 5.2.1)

reduce_plan: Write commands to reduce several targets down to one.

Description

Creates a new workflow plan data frame with the commands to do a reduction (i.e. to repeatedly apply a binary operator to pairs of targets to produce one target).

Usage

reduce_plan(plan = NULL, target = "target", begin = "", op = " + ",
  end = "", pairwise = TRUE)

Arguments

plan

workflow plan data frame of prespecified targets

target

name of the new reduced target

begin

character, code to place at the beginning of each step in the reduction

op

binary operator to apply in the reduction

end

character, code to place at the end of each step in the reduction

pairwise

logical, whether to create multiple new targets, one for each pair/step in the reduction (TRUE), or to do the reduction all in one command.

Value

A workflow plan data frame that aggregates multiple prespecified targets into one additional target downstream.

Examples

# NOT RUN {
# Workflow plan for datasets:
x_plan <- evaluate_plan(
  drake_plan(x = VALUE),
  wildcard = "VALUE",
  values = 1:8
)
# Create a new target from the sum of the others.
reduce_plan(x_plan, target = "x_sum", pairwise = FALSE)
# For memory efficiency and parallel computing,
# reduce pairwise:
reduce_plan(x_plan, target = "x_sum", pairwise = TRUE)
# Optionally define your own function and use it as the
# binary operator in the reduction.
x_plan <- evaluate_plan(
  drake_plan(x = VALUE),
  wildcard = "VALUE",
  values = 1:9
)
x_plan
reduce_plan(
  x_plan, target = "x_sum", pairwise = TRUE,
  begin = "fun(", op = ", ", end = ")"
)
# }