1 function A=blowup_matrix(A)
2 %
function A=blowup_matrix(A)
4 %
function inserts a row and a column of zeros between all rows and columns
5 % i.e. A=[1,2;3,4] becomes A=[1,0,2; 0,0,0; 3,0,4]
11 A_up = A(1:(2*i-1),:);
12 A_down = A((2*i):end,:);
13 A=[A_up; zeros(1,s);A_down];
18 A_left = A(:,1:(2*i-1));
19 A_right = A(:,(2*i):end);
20 A=[A_left, zeros(2*z-1,1), A_right];