ccd.design(nfactors=NULL, factor.names=NULL, default.levels=c(-1,1), ncube=NULL, resolution=if (identical(blocks,1) & is.null(ncube)) 5 else NULL, generators=NULL, ncenter = 4, alpha = "orthogonal", replications=1, block.name="Block.ccd", blocks=1, randomize=TRUE, seed=NULL, ...)-1 corresponds to the smaller, +1 to the larger value.generators
or blocks are specified, in which case the default is NULLFrF2 FrF2;
is EITHER
the number of blocks into which the experiment is subdivided
OR a character vector of names of independent factors that are used as block constructors
OR a vector or list of generators similar to generators.
In the latter case,
the differences to generators are
nfactors factors rather than the log2(nruns) base factors only,
If blocks is a single number, it must be a power of 2.
A blocked design can have at most nruns-blocks treatment
factors, but should usually have fewer than that.
If the experiment is randomized, randomization happens within blocks.
For the statistical and algorithmic background of blocked designs, see block.
design
with attributes attached. The data frame itself is in the original data scale.
The data frame desnum attached as attribute desnum is the coded design.
The attribute design.info is a list of various design properties.
The element type of that list is the character string ccd.
Besides the elements present in all class design objects,
there are the elements quantitative (vector with nfactor TRUE entries),
and a codings element usable in the coding functions available in the rsm
package, e.g. coded.data.Note that the row names and the standard order column in the
run.order attribute of ccd designs
are not in conventional order,
if the blocking routine blockpick.big was used.
In such situations, these should not be used as the basis for any calculations.
CentralCompositeDesigns.
Function ccd.design creates a central composite design from scratch.
It proceeds by generating a cube design with function FrF2 and then
augmenting this cube design using functions add.center from package
FrF2 for adding center points to the cube and subsequently function
ccd from package rsm for generating the star portion of
the design.
There are two main purposes for this function: one is to provide
central composite designs within the same syntax philosophy
used in packages DoE.base-package and FrF2.
The other is to automatically identify good (=resolution V) cube portions,
which can be achieved by using the resolution parameter. In comparison to direct usage of package ccd, the functions make the syntax closer to
that of the other packages in the DoE.wrapper suite and allow automatic selection of fractional
factorials as cubes.
Function ccd.design does not allow direct use of the estimable functionality
that is available in function FrF2. Nevertheless, ccd designs with a cube
based on the estimable functionality can be generated
by first using function FrF2 and subsequently applying
function ccd.augment. It may for example be interesting to use designs based on
estimability requirements for 2-factor interactions in cases where a resolution V cube
for the ccd is not feasible - of course, this does not allow to estimate the full second order model
and therefore generates a warning.
ccd.augment, add.center,
FrF2, lhs-package, rsm ccd.design(5) ## per default uses the resolution V design in 16 runs for the cube
ccd.design(5, ncube=32) ## uses the full factorial for the cube
ccd.design(5, ncenter=6, default.levels=c(-10,10))
## blocked design (requires ncube to be specified)
ccd.design(5, ncube=32, blocks=4)
## there is only one star point block
## for usage of other options, look at the FrF2 documentation
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