How od i generate random numbers whose sum is constant?

I want 100 random numbers bu their sum should be same.

[Torsten]

You want to generate 100 random numbers several times, I guess ? Because if you generate 100 random numbers once, there is only one sum.

[BHUKYA VENKATESH]

yes, I want to generate several times

Answer 1

[Bruno Luong]

If the numbers are supposed to be >= 0 with precribed sum, a simple method is

n = 100;
s = 10;

Y = -log(rand(1,n));
X = s * Y ./ sum(Y,2)
sum(X)

The justification of log is from the ubiased conditioning probability that I explain here:

https://uk.mathworks.com/matlabcentral/answers/715393-generate-random-number-with-total-sum-is-10?s_tid=srchtitle

Answer 2

[Bruno Luong]

Check this out

https://uk.mathworks.com/matlabcentral/fileexchange/9700-random-vectors-with-fixed-sum