make some matrices from one matrix without repeating the same numbers

Hi I have matrix A

    A=[1:1000]

I randomly made matrix B on the basis of 20 percent of (numel(A)) like that:

    B= randi(1000,[1 200])

then I calculate difference between this two matrix and named it sdB.

    sdB=setdiff(A,B)

now I want to determine matrix C on the basis of 20 percent of (numel(A) (it means 200 numbers) from matrix sdB. Then calculate difference between matrix B and C (or sdC). this process must be continue until in sum all 1000 numbers are determined. Is it possible to guide me please?

Answer 1

[Thorsten]

Using B= randi(1000,[1 200]) you don't get 200 unique numbers. If your goal is to split the numbers from 1 to 1000 in random order into 5 chunks of 200 numbers, use

 R = randperm(1000);
 for i = 1:5
   A(i,:) = R([1:200]+(i-1)*200);
 end

A(i,:) is then your i'th set of 200 numbers randomly picked from 1000, but without repetitions.

[fatema saba]

Thank you Thorsten, however is it possible to vectorise this code and concise it?

[Thorsten]

That's possible:

R = randperm(1000);
A = reshape(R, 200, [])';