seq_federer_atkinson: Federer and Atkinson (1964) 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 Federer and Atkinson (1964).

1 2	seq_federer_atkinson(D = 3, selection = 1, labels = 0:(D - 1), as_matrix = T, summary = T)

`D`	The number of treatments. Must be either three, four, or five. Defaults to `3`.
`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_federer_atkinson() supports the specification of designs from Federer and Atkinson (1964). Designs for three, four, or five 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 D = 3, there are two designs available (accessible by setting selection equal to one or two), for D = 4, there are two designs available (accessible by setting selection equal to one or two), and for D = 5, there is one design available (accessible by setting selection equal to 1). Ultimately, the (k,j)th element of the sequence 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.

Federer WT, Atkinson GF (1964) Tied-double-change-over designs. Biometrics 20:168-81.

# Federer and Atkinson (1964) designs for three treatments
federer_atkinson1        <- seq_federer_atkinson()
federer_atkinson2        <- seq_federer_atkinson(selection = 2)
# Using different labels
federer_atkinson1_ABC    <- seq_federer_atkinson(labels = LETTERS[1:3])
federer_atkinson2_ABC    <- seq_federer_atkinson(selection = 2,
                                                 labels = LETTERS[1:3])
# Returning in tibble form
federer_atkinson1_tibble <- seq_federer_atkinson(as_matrix = F)
federer_atkinson2_tibble <- seq_federer_atkinson(selection = 2,
                                                 as_matrix = F)