I want to change value of a variable after every 10 iterations

I am doing 100 iterations. I have a variable gamma that multiplies with a vector a. I want to update the value of gamma after every 10 iterations. I wrote a For loop but I can't seem to figure out how to update it after every ten iterations.

iter = 0;
while iter<100
    iter = iter + 1;
    a = vector;
    constt = sqrt(10);
    gamma = 10^-8;
        for k = 1:10
            f(?) = gamma(?) * a'*(1-a);
            gamma(k+1) = constt * gamma(k);
        end
end

I need to calculate f with different values of gamma after every 10 iterations. I am not sure what will be the indexing for f and gamma in the equation.

Answer 1

[Walter Roberson]

for iter = 1:100

k = 1 + floor((iter-1)/10)

[Ahmad Hasnain]

I use a while loop for iterations. So I do not need a FOR loop for changing values of gamma?

[Walter Roberson]

you are using aa fixed number of iterations so for is clearer . But whatever , use while if you like . The calculation I show is for after iter has been incremented.