How to generate a random array of 1*N matrix in which sum of all elements is 1 and numbers generate should be upto 1 decimlal place only.
1 vue (au cours des 30 derniers jours)
Afficher commentaires plus anciens
Abhinav
le 13 Nov 2014
Commenté : Roger Stafford
le 13 Nov 2014
For eg. [0.4 0.3 0.3] It should be generated randomly.
2 commentaires
Roger Stafford
le 13 Nov 2014
If N is large, restricting the array values to one decimal place only would force many of the values to be zero if I understand you correctly. Are you sure this is what you want?
Réponse acceptée
Roger Stafford
le 13 Nov 2014
Modifié(e) : Roger Stafford
le 13 Nov 2014
diff([0,sort(randi([0,10],1,N-1)),10])/10; % <-- Corrected
4 commentaires
Roger Stafford
le 13 Nov 2014
To avoid zeros you can do this, Abhinav:
x = (diff([0,sort(randi([0,10-N],1,N-1)),10-N])+ones(1,N))/10;
Note that with this restriction, N cannot be greater than 10. Otherwise there will be error messages.
As for an explanation, first, if your N numbers are each multiplied by ten, then they are integers and their sum must always be 10, which explains the division by 10 at the last step. Next, if 1 is subtracted from each integer, then their sum is 10-N, and they range from 0 to 10-N, which explains the addition of "ones(1,N)".
So now the equivalent problem is to find random integers ranging from 0 to 10-N whose sum is 10-N. The call "randi([0,10-N],1,N-1)" gives N-1 integers in this range and 'sort' arranges them in ascending order. The row vector
[0,sort(randi([0,10-N],1,N-1)),10-N]
consists of N+1 ascending integers which start with 0 and end with 10-N. If we perform a 'diff' on these, the resulting integers will all necessarily have a sum of 10-N because 0 and 10-N are the two end values of that vector. Also all the resulting integer differences must lie between 0 and 10-N. That is what was required in the above equivalent version. Therefore problem solved.
To get a better feeling for this solution you can separate out the parts of the code:
t1 = randi([0,10-N],1,N-1);
t2 = sort(t1);
t3 = [0,t2,10-N];
t4 = diff(t3);
t5 = t4 + ones(1,N);
t6 = t5/10;
and experiment with each step of the computation to see how it proceeds to a solution.
Plus de réponses (0)
Voir également
Catégories
En savoir plus sur Creating and Concatenating Matrices dans Help Center et File Exchange
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!