choosing random vectors for 3 VAriables
1 Ansicht (letzte 30 Tage)
Ältere Kommentare anzeigen
i have made a vector like this x(1,i), i=1 to 10e6 in a m.file(this is my output format ) now i want to choose randomly 10000 of them and then showing those vectors. i have 3 random variables that all of them produced in a format like [x(1,i), i=1 to 10e6 ] now what should i do if i want to have in my output 10e4 randomly selected for each 3 variables??i mean 10e4 vectors (selected randomly) for my 3 variables.
0 Kommentare
Akzeptierte Antwort
Paulo Silva
am 8 Jun. 2011
I don't understand 100% of your question but I will try
x1=randperm(10e6); %generates a permutation of values from 1 to 10e6
x2=x1(1:10e4); %get only the first 10e4 values
%replace x1 in the second line by your vector if needed
1 Kommentar
Sean de Wolski
am 8 Jun. 2011
And repeat Paulo's operation for the three variables. If you want all three variables to contain unique entries from x, then use x1 = randperm(10e6);x2 = x1(1:3*10e4) and extract each x2(1:10000);x2(10001:20000);etc.
Weitere Antworten (1)
Jan
am 8 Jun. 2011
If you do this once, Paulo's solution is fine. If you have to do this 1000s of times, it might be a problem that RANDPERM(10e6) takes 13 seconds (on my old 1.5GHz PentiumM). Then you could use the faster FEX: Shuffle:
Index = Shuffle(10e6, 'index', 10e4);
This replies 10e4 indices taken randomly out of 1:10e6 as the RANDPERM command, but it needs 0.05 seconds olny.
Nevertheless, the question is not getting clear to me also. Please give an example for the values of the 3 variables.
6 Kommentare
Jan
am 9 Jun. 2011
The question is still vague. Therefore I have to guess:
X = TruncatedGaussian(sigma, range, 1e7);
var1 = X(Shuffle(1e7, 'index', 1e5));
var2 = X(Shuffle(1e7, 'index', 1e5));
var3 = X(Shuffle(1e7, 'index', 1e5));
Or if the variables are not allowed to have common elements:
Index = Shuffle(1e7, 'index', 3*1e5);
var1 = X(Index(1:1e5));
var2 = X(Index(1e5+1:2*1e5));
var3 = X(Index(2*1e5+1:3*1e5));
Note: I've use the standard method "1e5" instead of your notation "10e4", which means "10.0 * 10^4".
If you want something else, please take the time to formulate all inputs and outputs exactly.
Siehe auch
Kategorien
Mehr zu Creating and Concatenating Matrices finden Sie in Help Center und File Exchange
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!