Incorrect code, A <- matrix(1, 2, 2) B <- matrix(2, 3, 2) A %*% B Produces Error in A %*% B : non-conformable arguments It would be helpful to show the matrix dimensions, Error in A %*% B : non-conformable arguments of dimensions (2, 2) and (3, 2) -- Joshua N. Pritikin, Ph.D. Virginia Institute for Psychiatric and Behavioral Genetics Virginia Commonwealth University PO Box 980126 800 E Leigh St, Biotech One, Suite 1-133 Richmond, VA 23219 http://exuberant-island.surge.sh