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Create a random Matrix

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Maurizio
Maurizio le 24 Oct 2011
I have a 8 column vector n*1. Can I create a Random matrix of n*8?
The function must take one value from each vector and create a matrix with 8 columns and n rows.
Please help me :-)
  2 commentaires
Jan
Jan le 24 Oct 2011
"I have a 8 column vector" sounds like a single vector. But "from each vector" might mean n vectors. Confusing.
Maurizio
Maurizio le 24 Oct 2011
I have 8 different variable. Each variable is a column vector (nx1).
What I need is to have as OUT a random matrix with 8 column and n rows. The value on the first OUT Column must be only the value of the first IN column

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Réponse acceptée

Andrei Bobrov
Andrei Bobrov le 24 Oct 2011
A1,A2,..,A8 - your vectors (nx1), let n = 5;
for j1 = 1:8, eval([sprintf('A%d',j1),'=randi(20,5,1)']); end
A = eval(['[',sprintf('A%d,',1:8),']'])
out=A(bsxfun(@plus,cell2mat(arrayfun(@(x)randperm(n)',(1:8),'un',0)),(0:7)*n))
  3 commentaires
Jan
Jan le 31 Oct 2011
@Maurizio: Accepting an answer means, that it solves your problem sufficiently.
Maurizio
Maurizio le 31 Oct 2011
@JAN: I accept but because create a random Matrix but as you can see from my comment Is that there was some problem about OUT columns values

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Plus de réponses (1)

Walter Roberson
Walter Roberson le 24 Oct 2011
rv(:,1) = randomvector1;
rv(:,2) = randomvector2;
rv(:,3) = randomvector3;
....
rv(:,4) = randomvector4;
rants = zeros(8, n);
for K = 1:n
rants(:,K) = A Random Selection of One Entry Per Column from rv
end
How to do "A Random Selection of One Entry Per Column from rv" is left to you to work on in more detail. I will hint that it involves using rand().
  3 commentaires
Maurizio
Maurizio le 30 Oct 2011
Can you help me what I need to write on the for loop please?
Walter Roberson
Walter Roberson le 30 Oct 2011
floor(1 + n * rand())
will give you a random row number.
If I say much more than I will be completing your assignment for you.

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