Randomly generate a matrix of zeros and ones with a non-uniform bias

Can anyone help me to generate a matrix of zeros and ones randomly without uniformly distributing like the function of "randint". Instead with the number of ones must be larger than zeros in an array.

For example, a matrix like this:

A= [ 1 1 1 1 0 1 0, 1 0 1 1 1 1 1, 1 1 0 1 1 0 0]

Answer 1

[Matt Fig]

Like this?

A = rand(1,21)>.3 % Increase number for less ones, decrease for more.

[Nurul]

Hi Matt, for the time being, i'm using your solution as it could give the ones more than zeros.

[Jack Nelson]

Thanks! :)

Answer 2

[Jos (10584)]

The following gives you a matrix with exactly a certain number of 1's

sizeR = [3 4] ;
num1 = 8 ;

R = zeros(sizeR)  % set all to zero
ix = randperm(numel(R)) % randomize the linear indices
ix = ix(1:num1) % select the first 
R(ix) = 1 % set the corresponding positions to 1

By the way, if the only values in R are 0 and 1 than logical arrays may be worthwhile to explore, as they are less memory consuming than double arrays.

[Nima Mahanfar]

Thanks, this was very helpful. Is there a way to make these ones being adjacent elements? example for 6x3 matrix with two 1's: [1 1 0 0 0 0; 0 0 0 0 0 0; 0 0 0 0 0 0]

[Nima Mahanfar]

Thanks, this was very helpful. Is there a way to make these ones being adjacent elements? example for 6x3 matrix with two 1's: [1 1 0 0 0 0; 0 0 0 0 0 0; 0 0 0 0 0 0]

[Nima Mahanfar]

Thanks, this was very helpful. Is there a way to make these ones being adjacent elements? example for 6x3 matrix with two 1's: [1 1 0 0 0 0; 0 0 0 0 0 0; 0 0 0 0 0 0]

[Nima Mahanfar]

Thanks, this was very helpful. Is there a way to make these ones being adjacent elements? example for 6x3 matrix with two 1's: [1 1 0 0 0 0; 0 0 0 0 0 0; 0 0 0 0 0 0]

[Nima Mahanfar]

Thanks, this was very helpful. Is there a way to make these ones being adjacent elements? example for 6x3 matrix with two 1's: [1 1 0 0 0 0; 0 0 0 0 0 0; 0 0 0 0 0 0]

[Nima Mahanfar]

Thanks, this was very helpful. Is there a way to make these ones being adjacent elements? example for 6x3 matrix with two 1's: [1 1 0 0 0 0; 0 0 0 0 0 0; 0 0 0 0 0 0]

[Nima Mahanfar]

Thanks, this was very helpful. Is there a way to make these ones being adjacent elements? example for 6x3 matrix with two 1's: [1 1 0 0 0 0; 0 0 0 0 0 0; 0 0 0 0 0 0]

Answer 3

[Walter Roberson]

0 + (rand(7,3) > 0.4)

[Bruno Luong]

Not that matter, but in light of the recent discussion, in order to generate a 0.4 probability of zeros, the more accurate RAND() cut is:

s = 2^(-53)

cut = 0.4*(1-s)+s/2

r = rand > cut

Answer 4

[Nurul]

Thanks for your help. Its helped me a lot.

[Ned Gulley]

Nurul, the best thanks is to accept one of the answers.