utilitiesCat {FrF2}R Documentation

~~ Internal utility functions and user-visible constants for working with regular fractional factorials ~~

Description

~~ Internal functions, mainly for deriving words, alias structures and so forth from catalogue information for regular 2-level fractional factorials. They need not be accessed for normal use of the package - some of them may be made user-usable for future versions of the package.

The constants Yates and Letters are user-visible, as they can be useful for expert users. ~~

Usage

mult.gen(liste) 
mult.gen.a(string.vec)
words.all(k, gen, max.length=7)
gen.check(k, gen)
alias3fi(k, gen)
Yates
Letters

Arguments

liste list of words in terms of vectors of factor numbers to be combined into one new word
string.vec vector of words in terms of factor letter combinations (e.g. “ABC”) to be combined into one new word
k number of factors spanning a full factorial with the desired number of runs (i.e. log2(nruns))
gen generators in any admissible format (gen.check transforms any admissible format to the default needed for calculations))
max.length the maximum word length to be calculated for the words list; in large design, choosing this to be 4 or 5 may substantially speed things up!

Details

Yates and Letters are user-visible constants that are useful in design construction:

Yates is a list of design column generators in Yates order (for 4096 runs), e.g. Yates[1:8] is identical to

list(1,2,c(1,2),3,c(1,3),c(2,3),c(1,2,3)).

Letters is the vector of all capital and lower case letters of the Roman alphabet except I and i. It is used for default factor names and has been obtained as

Letters <- c(LETTERS[-9],letters[-9]).

Value

mult.gen and mult.gen.a determine a new word as the product of the argument words (numeric vector or character string respectively), words.all calculates a word list object with word length pattern, the word list itself and a max.length entry, gen.check produces a list of vectors with integers from 1 to k for denoting the generators, which may have come as a vector of factor letter combinations or a vector of column numbers in Yates order, and alias3fi calculates an alias pattern based on the structure of the design (less demanding than the word list approach.
Yates and Letters are user-visible constants (cf. details section).

Note

This package is currently under intensive development. Substantial changes are to be expected in the near future.

Author(s)

Ulrike Groemping

References

Hedayat, A.S., Sloane, N.J.A. and Stufken, J. (1999) Orthogonal Arrays: Theory and Applications, Springer, New York.

See Also

~~See Also FrF2


[Package FrF2 version 0.9-1 Index]