Calculate the correlation of the design. The function gets the design from
the design object before passing it to cor from stats.
This is a wrapper around cor.
Usage
cor(x, ...)
Value
A matrix with correlations
Arguments
x
A model object of class 'spdesign'
...
Additional parameters passed to the function
Details
Note that when your design includes constants, the function will print a
warning because the standard deviation of a constant is 0.