| opttodes {crossdes} | R Documentation |
The function Dopt of the library Dopt is used to construct balanced incomplete block designs
(BIBDs). The design is assigned to a matrix where rows represent blocks (subjects) and
columns represent periods.
opttodes(trt, b, k, iter = 50)
trt |
An integer > 1 giving the number of treatments of the design. |
b |
An integer > 1 giving the number of rows (subjects) of the design. |
k |
An integer > 1 giving the number of columns (periods) of the design. |
iter |
The number of iterations of the function Dopt |
The function Dopt tries to find a D-optimal block design for the specified parameters.
The resulting design need not be a BIBD.
The necessary conditions for the existence are that bk/trt and
bk(k-1)/(trt(trt-1)) positive intergers.
They are NOT checked automatically.
Even if they are fulfilled, there need not be a BIBD.
If no BIBD is found, the function is iterated.
If no BIBD is found after iter iterations, the search is terminated.
In any case, the resulting design is checked by the function isGYD, the result is
displayed on the screen and the resulting design matrix is returned.
A matrix that represents the experimental design.
This function requires the package Dopt.
As of May 13 2004, CRAN states that Dopt is a package in development and that such packages may be unstable.
As indicated above, the returned design is not necessarily a BIBD design.
Oliver Sailer sailer@statistik.uni-dortmund.de
opttodes(10,30,4) # BIBD opttodes(3,3,2) # BIBD, even GYD opttodes(5,5,3, 100) # There is no BIBD for these parameters