MATLAB: How to randomly select an element in adjacent entries in a matrix in for loop

Question

here's my code:

    % code

  for j=1:tmax
    for i=1:n
    if mat(i)==0 && rand() < r*(1-(zerfre)^2);
        idx = 1 + fix(rand(1,1)*numel(mat)); 
        mat(i)=mat(idx);
    elseif mat(i)==1 && rand() < r*(1-(onefre)^2);
        idx = 1 + fix(rand(1,1)*numel(mat));
        mat(i)= mat(idx);
    elseif mat(i)==2 && rand() < r*(1-(twofre)^2);
        idx = 1 + fix(rand(1,1)*numel(mat));
        mat(i)= mat(idx);
    elseif mat(i)==3 && rand() < r*(1-(thrfre)^2);
        idx = 1 + fix(rand(1,1)*numel(mat));
        mat(i)= mat(idx);
    elseif mat(i)==4 && rand() < r*(1-(foufre)^2);
        idx = 1 + fix(rand(1,1)*numel(mat));
        mat(i)= mat(idx);
    elseif mat(i)==5 && rand() < r*(1-(fivfre)^2);
        idx = 1 + fix(rand(1,1)*numel(mat));
        mat(i)= mat(idx);
    end
    last=mat;
    end  
    % code

Basically I'm updating my initial matrix mat with probability rules. What the rule does is, with some probability, it's replacing the entry with another entry that's randomly selected from the rest of the entire matrix.

Instead of this, I need to randomly select an element from an adjacent neighbourhood of entries, then replace the old entry with that.

By adjacent I mean within the closest 10*10 entries.

How would I do this?

Thanks a lot for your help!

Answer 1

I can answer my own question in case others are looking for solutions!

go to link:

http://www.mathworks.com/matlabcentral/newsreader/view_thread/148383

playing with indices will give you the immediate entries. So far this seems like the best option I can get.