vvinichenko

shiftMatrix <- function(mx, dr, dc) {
	#Shift the matrix by dr (delta r) rows and dc columns
	#by adding e.g. dr rows of zeros and removing dr rows from the other side 
	
	nr <- nrow(mx)
	nc <- ncol(mx)
	
	#If the matrix is shifted by more than its nrow or ncol, we get a matrix of zeros 
	if (abs(dr) >= nr || abs(dc) >= nc) {
		mx <- matrix(0, nrow = nr, ncol = nc)