seq_davis_hall: Davis and Hall (1969) cross-over design specification
In mjg211/xover: Design and analysis of cross-over clinical trials

Description Usage Arguments Details Value Author(s) References Examples

Specifies cross-over designs from Davis and Hall (1969).

1 2	seq_davis_hall(D = 6, selection = 1, labels = 0:(D - 1), as_matrix = T, summary = T)

`D`	The number of treatments. Must be either six, seven, eight, or nine. Defaults to `6`.
`selection`	A single `numeric` integer indicating which design to return, for the chosen value of `D`. See Details for information on supported values.
`labels`	A `vector` of labels for the treatments. Should be of `length` `D`, containing unique elements. Defaults to `0:(D - 1)`.
`as_matrix`	A `logical` variable indicating whether the design should be returned as a `matrix`, or a `tibble`. Defaults to `T`.
`summary`	A `logical` variable indicating whether a summary of the function's progress should be printed to the console. Defaults to `T`.

seq_davis_hall() supports the specification of designs from Davis and Hall (1969). Designs for six through nine treatments (see D) are supported, for any chosen treatment labels (see labels). In addition, the designs can be returned in matrix or tibble form (see as_matrix).

Precisely, for each supported value of D, there are three designs available (accessible by setting selection equal to one, two, or three). Ultimately, the (k,j)th element of the cross-over design matrix corresponds to the treatment a subject on the kth sequence would receive in the jth period.

Either a matrix if as_matrix = T (with rows corresponding to sequences and columns to periods), or a tibble if as_matrix = F (with rows corresponding to a particular period on a particular sequence). In either case, the returned object will have class xover_seq.

Based on data from the Crossover package by Kornelius Rohmeyer.

Davis AW, Hall WB (1969) Cyclic change-over designs. Biometrika 56:283-93.

# Davis and Hall (1969) designs for six treatments
davis_hall1        <- seq_davis_hall()
davis_hall2        <- seq_davis_hall(selection = 2)
davis_hall3        <- seq_davis_hall(selection = 3)
# Using different labels
davis_hall1_ABCDEF <- seq_davis_hall(labels = LETTERS[1:6])
davis_hall2_ABCDEF <- seq_davis_hall(selection = 2, labels = LETTERS[1:6])
davis_hall3_ABCDEF <- seq_davis_hall(selection = 3, labels = LETTERS[1:6])
# Returning in tibble form
davis_hall1_tibble <- seq_davis_hall(as_matrix = F)
davis_hall2_tibble <- seq_davis_hall(selection = 2, as_matrix = F)
davis_hall3_tibble <- seq_davis_hall(selection = 3, as_matrix = F)