Create a vector by selection randomly vectors

1 view (last 30 days)
Hi all,
I have 4 vectors
A=[1 2 3 4 5];
B=[0 2 5 6 19];
C=[0 0 1 3 0];
D=[1 0 1 15 0];
And I want to create vectors by randomly selecting from the list above, so that I take something like:
Vector1=[B;C;D;A]
Vector2=[C;D;A;B]
Vector3=[A;D;C;B]
.
.
.
etc.

Accepted Answer

Stephan
Stephan on 5 Nov 2018
Edited: Stephan on 5 Nov 2018
A=[1 2 3 4 5];
B=[0 2 5 6 19];
C=[0 0 1 3 0];
D=[1 0 1 15 0];
pool = [A; B; C; D];
n = 10 % Number of vectors to create
for k = 1:n
idx = randperm(4);
result(k,:) = [pool(idx(1),:), pool(idx(2),:), pool(idx(3),:), pool(idx(4),:)]
end
This code stores the created vectors in the lines of a Matrix. Access them with:
vector_1 = result(1,:)
vector_2 = result(2,:)
.
.
.
vector_n = result(n,:)
Best regards
Stephan

More Answers (2)

Stephen23
Stephen23 on 5 Nov 2018
Edited: Stephen23 on 5 Nov 2018
Having separate vectors is a pain to work with, so the first thing to do is to put them into one matrix M:
>> M = [1,2,3,4,5;0,2,5,6,19;0,0,1,3,0;1,0,1,15,0]
M =
1 2 3 4 5
0 2 5 6 19
0 0 1 3 0
1 0 1 15 0
>> N = 7; % how many output matrices
>> [~,R] = sort(rand(N,size(M,1)),2);
>> C = cellfun(@(r)M(r,:),num2cell(R,2),'uni',0);
>> C{:}
ans =
0 0 1 3 0
1 0 1 15 0
0 2 5 6 19
1 2 3 4 5
ans =
1 2 3 4 5
0 2 5 6 19
1 0 1 15 0
0 0 1 3 0
ans =
1 2 3 4 5
1 0 1 15 0
0 0 1 3 0
0 2 5 6 19
ans =
1 2 3 4 5
1 0 1 15 0
0 2 5 6 19
0 0 1 3 0
ans =
0 0 1 3 0
1 0 1 15 0
1 2 3 4 5
0 2 5 6 19
ans =
0 2 5 6 19
0 0 1 3 0
1 0 1 15 0
1 2 3 4 5
ans =
0 2 5 6 19
1 0 1 15 0
1 2 3 4 5
0 0 1 3 0

madhan ravi
madhan ravi on 5 Nov 2018
Edited: madhan ravi on 5 Nov 2018
EDITED
A=[1 2 3 4 5]; B=[0 2 5 6 19]; C=[0 0 1 3 0]; D=[1 0 1 15 0];
vectors = [A;B;C;D];
n = 10 ; % specify n to create n number of vectors
VECTORS = cell(1,n); %PREALLOCATION
for i = 1:n
VECTORS{i}=[vectors(randsample((1:4),4) ,:)];
end
celldisp(VECTORS)
  1 Comment
Stephen23
Stephen23 on 5 Nov 2018
Edited: Stephen23 on 5 Nov 2018
Note that randi can repeat values in its output array, so this answer does not match the examples given (which do not repeat any rows and are all row permutations of the same matrix).
For example:
>> randi([1,4],2,2)
ans =
1 4
1 4
Would return A,A,D,D: where are B and C ?
One solution is to use randperm, as Stephan Jung's answer shows.

Sign in to comment.

Categories

Find more on Dates and Time in Help Center and File Exchange

Tags

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!