This is one option:
r = 0.5;
idx = randperm(20, ceil(r*20));
rv = zeros(1,20);
rv(idx) = 1;
The logic is relatively straightforward: ‘idx’ uses rendperm to generate a matrix of index positions, then generates ‘rv’ and uses ‘idx’ to determine the r*20 values that are set to 1.
With r = 0.5, this yields:
rv =
Columns 1 through 17
0 1 0 0 1 0 0 1 1 1 1 0 1 0 0 1 1
Columns 18 through 20
1 0 0
