Randomly generated row matrix B with constraints?

Matrix A which is generated based on a calculation A=[2 1 1 2]

I need:

Matrix B (B is equal to the size of A) needs to be randomly generated so that each of its entries (1,i) are no larger than the respective entries in Matrix A (1,i).

I also need a 0 to be a possible randomly generated number in Matrix B

Any help, much appreciated. I can not figure a way for randi to apply this constraint to the individual columns.

[laurie]

for pop = 2:1:20
     for ii = 1:1:4

           A(ii) = ((Data.tend(1,pop-1)-Data.duration(1,pop-1)+1) - Data.tstart(1,pop-1)); %Matrix A

           B(ii) = randi([0, A(ii)], 1); %Matrix B
           chrom(ii)  = Population(pop-1).chrom(pop-1) + B(ii);
      end

       Population(pop).chrom = int2str(chrom);
       clear chrom
   end

Does not stay within upper and lower bounds after 1st iteration.

Answer 1

[Roger Stafford]

I don't understand what you mean in the sentence "I also need a 0 to be a possible randomly generated number in Matrix B". For the other part try this:

   B = A.*rand(size(A));

For each element in A, the corresponding element in B will lie somewhere between 0 and the A element value.

If you expect the elements of B to be integers, that is quite another matter.

[laurie]

Thank you but..

This would not enforce the constraint that the integer values in column 1:1:4 of B be less than or equal to the values of column 1:1:4 of A

[Roger Stafford]

Are you saying that the values in B should be integers? You should make that clear. The code I gave does not do that. Its values are almost all fractional. Also please be clear about what you expect the lower bounds in B values to be. Is it zero? Is it one? And finally what did you mean by the sentence I asked about?

[laurie]

1.The values should be integers

2. The lower bounds of B should be 0 and the upper bound for B(1,i) should be A(1,i); where i is the columns.

3.As for the sentence you asked about, I was referring to the lower bounds. I was not very clear, sorry about that.

Answer 2

[Greig]

I guess this is what you are looking for?

for ii = 1:length(A)
B(ii) = randi([0, A(ii)], 1);
end

It is not so clear exactly what you are after, could you clarify a bit more please.

[laurie]

Greig please see the code I've attached.

Answer 3

[Roger Stafford]

I think this is what you want, Laurie, assuming A elements are all non-negative integers.

   B = floor((A+1).*rand(size(A)));