If the random variables have uniform distribution you can generate it by using rand() function and if they have normal distribution you may use randn(). For isntant an mxn matrix whose elements are random numbers with formal distribution will be generate by randn(m,n).
Since you want to generate a vector go for A = rand(1, n)*pi/2 where n is t he no of elements in the vector followed by A = sort (A) this will give you a vector A whose elements are less than pi/2