R/blkdiag.R

In pracma: Practical Numerical Math Functions

blkdiag <-function(...) {
	dots <- list(...)
	if (! all(sapply(dots, is.matrix)) ||
	    ! all(sapply(dots, is.numeric)) )
		stop("All input arguments in '...' must be numeric matrices")

	nrows <- sapply(dots, nrow)
	ncols <- sapply(dots, ncol)
	if (any(nrows == 0) || any(ncols == 0))
		stop("All input matrices '...' must be non-empty.")

	n <- sum(nrows)
	N <- c(0, cumsum(nrows))
	m <- sum(ncols)
	M <- c(0, cumsum(ncols))

	A <- matrix(0, nrow = n, ncol = m)

	k <- length(dots)
	for (i in 1:k) {
		A[(N[i]+1):N[i+1], (M[i]+1):M[i+1]] <- dots[[i]]
	}


	return(A)
}