redesign {DeclareDesign}

R Documentation

Redesign

Description

redesign quickly generates a design from an existing one by resetting symbols used in design handler parameters in a step's environment (Advanced).

Usage

redesign(design, ..., expand = TRUE)

Arguments

design	An object of class design.
...	Arguments to redesign e.g., n = 100. If redesigning multiple arguments, they must be specified as a named list.
expand	If TRUE, redesign using the crossproduct of ..., otherwise recycle them.

Details

Warning: redesign will edit any symbol in your design, but if the symbol you attempt to change does not exist in a step's environment no changes will be made and no error or warning will be issued.

Please note that redesign functionality is experimental and may be changed in future versions.

Value

A design, or, in the case of multiple values being passed onto ..., a 'by'-list of designs.

Examples

n <- 500
population <- declare_model(N = 1000)
sampling <- declare_sampling(S = complete_rs(N, n = n), 
                             legacy = FALSE)
design <- population + sampling

# returns a single, modified design
modified_design <- redesign(design, n = 200)

# returns a list of six modified designs
design_vary_N <- redesign(design, n = seq(400, 900, 100))

# When redesigning with arguments that are vectors,
# use list() in redesign, with each list item
# representing a design you wish to create

prob_each <- c(.1, .5, .4)

assignment <- declare_assignment(
  Z = complete_ra(prob_each = prob_each), 
  legacy = FALSE)

design <- population + assignment

# returns two designs

designs_vary_prob_each <- redesign(
  design,
  prob_each = list(c(.2, .5, .3), c(0, .5, .5)))


# To illustrate what does and does not get edited by redesign, 
# consider the following three designs. In the first two, argument
# X is called from the step's environment; in the third it is not.
# Using redesign will alter the role of X in the first two designs
# but not the third one.

X <- 3
f <- function(b, X) b*X
g <- function(b) b*X

design1 <- declare_model(N = 1, A = X)       + NULL
design2 <- declare_model(N = 1, A = f(2, X)) + NULL
design3 <- declare_model(N = 1, A = g(2))    + NULL

draw_data(design1)
draw_data(design2)
draw_data(design3)

draw_data(redesign(design1, X=0))
draw_data(redesign(design2, X=0))
draw_data(redesign(design3, X=0))

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