Square of 20 random number sum up to 1

The code below generate 20random number which their sum up to 1. r = rand(1, 20); % Start with 20 random numbers. r = r / sum(r) % Normalize so the sum is 1. theSum = sum(r) % Check to make sure. Should be 1

How we can generates 20 random number in which their squares are sum up to 1.

Answer 1

[Dimitris Kalogiros]

clear ; clc;

N=20;
r=rand(1,N);

normFactor=sqrt(sum(r.^2));
r=r/normFactor;

figure; 
plot(r,'bo');
zoom on; grid on;
xlabel('index'); ylabel('random number');

S=sum(r.^2);
fprintf('sum of square random numbers :  %f \n', S);

If you run this script :

Answer 2

[Torsten]

r = r / sqrt(sum(r.^2))

Best wishes

Torsten.