A question about multiplying the matrix below that is a variation Henderson's mixed model equations:
|M1 M2| |M5 M6| |M3 M4| |M7 M8|
whre M1-M8 are matrices. I'm not exactly sure what the result should look like. I think it should result in a single matrix as I need to take the trace of the result. Feedback appreciated.
EDIT: I don't know what happened to my edits from last night. Here's an example of two matrices: http://escholarship.org/uc/item/9wc564c1#page-34 (Eq 2.2). Maybe the best approach is to consider the left and right matrix as m*(p+q)X*m*(p+q) matrices where X is is nXp, Z is nXq and m is the number of clusters. Then you don't have to worry about the subcomponents. It's simple (but very large in some cases) crossproducts of two matrices. Sound right?