Generate a random matrix with 4 specifik values

hello i want to generate a random matrix tnat has 16 rows and 10^5 coloums that contains 4 differen values [-1,1,-j,j]. can anyone help me

Answer 1

[Jeff Miller]

maybe this?

j = 2.5;  % insert whatever value of j you want to use
vals = [1,-1, j, -j];
pos = randi(numel(vals),15,10^5);
randmatrix = vals(pos);