is.spread {IsoCheck}

Boolean check for a proper Spread

Description

Checks whether or not the input is a proper balanced (t-1)-spread of PG(n-1,2).

Usage

is.spread(spr, printstatements = TRUE)

Arguments

spr

A balanced spread of PG(n-1,2) stored as a three dimensional binary array (see Details and Examples of checkSpreadEquivalence).

printstatements

A Boolean indicating whether or not to print possible reasons for not being a spread if the input is not a spread.

Details

Checks whether or not the input is a proper balanced (t-1)-spread of PG(n-1,2). The spread should be formatted as a 3-dimensional array with spr[i,j,k] indicating whether or not the ith basic factor is present in the jth effect of the kth flat of spr. See Spencer et al. (2019) for details.

Value

A Boolean indicating whether or not the input is a spread.

Author(s)

Neil Spencer, Pritam Ranjan, Franklin Mendivil

References

Spencer, N.A., Ranjan, P., and Mendivil, F., (2019), "Isomorphism Check for 2^n Factorial Designs with Randomization Restrictions", Journal of Statistical Theory and Practice, 13(60),1-24 [https://doi.org/10.1007/s42519-019-0064-5]

See Also

is.star for checking if the input is a balanced covering star.
checkSpreadIsomorphism for checking the isomorphism of balanced spreads.
checkStarIsomorphism for checking the isomorphism of balanced covering stars.

Examples

## Example 1: checking whether "spreadn4t2a" is a proper spread
data(spreadn4t2a)
is.spread(spreadn4t2a)



## Example 2: checking whether "starn5t3a" is a proper spread
data(starn5t3a)
is.spread(starn5t3a)