Index exceeds matrix dimensions. Error in rough (line 62) x1(r(1)+1,​r(2)+1)=xx​x(i,j);

am unable to shuffle back due to index problem please anyone help me out

clear all
clc
g=imread('cameraman.tif');
% g=double(g)/255;
subplot(231)
imshow(g)
original=g;
[m,n]=size(g);
mo=m;
num = 12;
K=10.^10;
% K=19;
%....................Shuffling.......................
 disp('........................Started Shuffling.....................')
%Tinkerbell shuffling
a=0.3;b=0.6000;c=2.0;d=0.27;
for k= 1:num
for i=1:m
    for j=1:n
      r = mod([round(abs((i^2)-(j^2)+(a*i)+(b*j))),round(abs((2*i*j)+(c*i)+(d*j)))], [m,n]);
%     r = mod([(i+j),(j+K*sin(((i+1)*n)/2*pi))],mo);
%     r = [((i-1)+(K*sin(j-1))),((j-1)+i)];
%     r = uint8(r);
      ggg(i,j)=g(r(1)+1,r(2)+1);
%       ggg(i,j)=g(r(1),r(2));
      end
  end
    g=ggg;
  end
   subplot(232)
   x=ggg;
   imshow(ggg,[]);
   title('Tinkerbell shuffled')
   %henon Shuffling
  [m,n]=size(x);
   a = 1.4;b=0.3;
  % num_iter=input('Enter the round for Arnold shuffling');
  num_iter = 5;
  %     a=1.4;
  %     b=0.3;
   for k=1:num_iter
  for i=1:m
      for j=1:m
          r = mod([round(abs(1-(a*(i^2))+j)),round(abs(b*i))],[m n]);
           xxx(i,j)=x(r(1)+1,r(2)+1);
       end
   end
    x=xxx;
   end
   subplot(233)
   imshow(xxx);
   title('henon Shuffled Image')
   save xxx x
   disp('........................Shuffling process completed succesfully.....................')
   %...................Inverse Shufling.............................
   disp('........................Started Inverse Shuffling.....................')
   %Henon Inverse Shuffling
   for k=1:num_iter
  for i=1:m
      for j=1:n
  r = mod([round(abs(1-(a*(i^2))+j)),round(abs(b*i))],[m n]);
  x1(r(1)+1,r(2)+1)=xxx(i,j);
       end
   end
    xxx=x1;
   end
   subplot(234)
   imshow(x1);
   title('henon Inverse Shuffled')
%Tinkerbell inverse shuffling
 a=0.3;b=0.6000;c=2.0;d=0.27;
for k=1:num
for i=1:m
    for j=1:n
         r = mod([round(abs((i^2)-(j^2)+(a*i)+(b*j))),round(abs((2*i*j)+(c*i)+(d*j)))], [m,n]);

            g1(r(1)+1,r(2)+1)=x1(i,j); 
         end
     end
      xxx=g1;
    end
     subplot(224)
     imshow(g1)
     title('Tinkerbell_inverse_shuffled')
      disp('........................Inverse Shuffling process completed succesfully.....................')
     psnr = psnr(g1,original)
     ssim=ssim(g1,original)