could anyone help me how to avoid repetition of the same number of clusters

I am having totally 4 users in my system with respect to the following code:

meas=[1 2;
    3 4;
    5 6;
    7 8]
particles = 2;
iterations =2;
for t=1:iterations
    for p=1:particles
        cluster=size(meas,1)
        clusters= randi(cluster,1,1)
        D=partitions(cluster,clusters)
        total_number_of_partitions = length(D)
        idx=1
        B = D(idx)
        partdisp(B)
    end
end

When i run the code it executes and gives the number and formation of clusters for each particle on every iteration.

But sometimes it display the same set of clusters on different iteration.

As i have used idx=1 i think it displays the same set of clusters.could anyone please help me how to modify it such that the set of clusters needs to be changed on each and every iteration with respect to each particle.