how to generate floating points randomly????

Hello! i am new in matlab and need help, as em writing code for generating matrix of size 20-by-4. rowsize=20, colsize=4 and need to generate between [0 1], suppose i want matrix having random values like [0.25 0.5 0.05 0.20] and so on.... but when i run my code then it returns me 20-by-4 matrix of 0's and 1's.....which function i should use to get required results...please help and thanks in advance..

 { matrix_rand=randint(rowsize, colsize, [0 1]); it returns
     1     0     0     0
     1     1     1     0
     1     1     0     1
     0     0     0     0
     0     1     0     0
     1     1     1     1
     0     1     0     0
     1     1     0     0
     1     1     1     0
     0     0     0     1
     1     1     0     1
     1     0     1     1
     1     0     0     1
     1     0     0     0
     1     1     1     0
     0     1     0     1
     1     0     0     1
     0     0     0     1
     1     1     0     0 
but when i write rand(), then it returns nothing

Answer 1

[David Young]

matrix_rand = rand(rowsize, colsize);

[Talat]

Sory, i should elaborate my problem clearly.... i also want that sum of each row should be "1" suppose[0.25 0.5 0.05 0.20], if add these values then i get '1'... plz help me how should i give the limits also.....

[Talat]

hello David, plz help me to resolve problem..... thanx

[David Young]

You can make the sum of each row add to 1 like this:

matrix_rand_normalised = bsxfun(@rdivide, matrix_rand, sum(matrix_rand,2))

[Walter Roberson]

Please do *not* use the normalization method! It leads to bias in the generated numbers! Use Roger Stafford's method instead.

[Talat]

Yes! I have done my work with Roger Stafford's method ... and got results...Thanx both of you guys for suggestions....

Answer 2

[Walter Roberson]

Roger Stafford has a MATLAB File Exchange contribution for generating random numbers with a fixed sum. See http://www.mathworks.com/matlabcentral/fileexchange/9700-random-vectors-with-fixed-sum

[Talat]

Thanks sooooo much... i got it... it will help me for sure