find.BIB {crossdes}

Generation of Balanced Incomplete Block Designs Using the Package AlgDesign

Description

The function optBlock of the library AlgDesign is used to search for balanced incomplete block designs (BIBDs). The design is assigned to a matrix where rows represent blocks (subjects) and columns represent periods.

Usage

find.BIB(trt, b, k, iter = 30)

Arguments

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 optBlock

Details

The function optBlock 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 \frac{bk}{trt} and \frac{bk(k-1)}{trt(trt-1)} positive integers. 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. The resulting design should be checked by the user applying isGYD.

Value

A matrix that represents the experimental design.

Note

As indicated above, the returned design is not necessarily a BIBD design.

Author(s)

Oliver Sailer

References

Wheeler, R.E. (2004). optBlock. AlgDesign. The R project for statistical computing http://www.r-project.org/

See Also

get.plan, optBlock

Examples

find.BIB(10,30,4)       # BIBD
find.BIB(3,3,3)         # BIBD 
find.BIB(5,5,3, 100)    # There is no BIBD for these parameters   
# isGYD(find.BIB(5,5,3, 100))