How to make recursive for loop

I am trying to make recursive for loop for given for loop

sample program to achieve:

k=0;
k_prev1=0;
   k_prev=0;
for t= 1:2
   for i=1:2

        for j=1:3
          k=k+1;
        end
          k_new= k_prev+k;
          k_prev=k_new;
          k=k_new;
     end
      k_new= k_prev1+k;
      k_prev1=k_new;
      k=k_new;
  end

My code is like this with two functions

function1

    function  x = fun(y,cmax)

    k=length(cmax);

    x_prev=0;
    x_new=0;

    for i= 1:cmax(k)
         if y == 1
          x = fun1(y,cmax,x_new);
          x_new  = x_prev+x; 
          x_prev= x_new;
          x=x_new;
         elseif y >=2
              x= fun(y-1,cmax);
         end

     end

end

and another function is

    function u = fun1(x,cmax,x_new)

     if x==1
         u=0;
      for i = 1:cmax(x)
        if x_new > 0
            x_new= x_new+1;
        else    
          u= u+1;  
        end

    end
    if(x_new >0)
      u=x_new;
    end
     x_new=0;
  end

and the function call is like

cmax=[3,2,2];
fun(3,cmax)

And I could not get result. but it was working fine for 2 for loops. But not for more than two.

my aim is to be able to generate 5 to 7 for for loops . And thought recursive looping would help.

Any help is highly appreciated.

Answer 1

[Walter Roberson]

I recommend the "odometer" pattern when the number of for loops must be handled dynamically.

https://www.mathworks.com/matlabcentral/answers/357969-using-recursive-function-to-calculate-all-possible-peptide-combinations#answer_282766