random number with fixed summation

I randomly generated the matrix f1; where R is 8 and T is 11. In the following we have f1.

The summation of each column should have a fixed value k, for example k=4. I found the "randfixedsum" function that perfectly generates random number with fixed summation. But the elements are not zero and 1. Could you please help me to change f1 to a matrix that the summation of each column is exactly k.

    f1 =

     1     0     1     0     0     0     0     1     1     0     0
     1     0     0     0     0     1     1     0     1     0     0
     1     0     0     1     1     1     0     0     0     0     0
     1     0     1     1     0     0     1     1     1     1     1
     1     1     0     1     0     0     0     1     1     1     0
     0     1     1     0     1     0     1     0     1     1     0
     0     1     1     0     0     0     0     1     1     0     0
     0     1     1     1     1     0     1     0     1     1     0

Answer 1

[Roger Stafford]

Use the ‘randperm’ function on each column of f1:

   f1 = zeros(8,11)
   for ix = 1:size(f1,2)
     f1(randperm(size(f1,1),k),ix) = 1;
   end

[rezi raf]

thank you so much!

Answer 2

[Walter Roberson]

There are multiple ways to handle this, but the easiest way is just to round() the numbers.