How to spread out an arry of matrix randomly

I have random matrix like this

   [2 2 2 2 1 1 1 1 1 -1 -1 -1 -1 -1]

and depend to the result of calculation number of 2 1 -1 will be different but i want to spread these numbers randomly like this e.g. [2 1 2 -1 1 1 2 -1 2 -1 -1 2 ]

how should i do this?

Answer 1

[Walter Roberson]

YourVector(randperm(length(YourVector)))

[Hamid Reza Barzegar]

   first=100;
   Second=50;
   Third=50;
   Alloc_Sc=[2*ones(1,first),ones(1,Second),-1*ones(1,Third)];
   Alloc_Sc2=Alloc_Sc(length(randperm(Alloc_Sc)));

it shows the error:

Error using randperm Size inputs must be scalar.

[Stephen23]

@Hamid Reza Barzegar: Walter Roberson's answer clearly uses randperm(length(...)). You have written length(randperm(...).

Answer 2

[Roger Stafford]

Let n be the desired length of the result and let a = [2 1 -1] :

   p = randi(3,n,1);    % <-- Corrected
   v = a(p(randperm(n)));  % v is your result   % <-- Corrected

[Hamid Reza Barzegar]

 Nsc=200;
p = randi(3,Nsc);
 v = Alloc_Sc(p(randperm(Nsc)));  % v is your result

data which is store in v is just vector 1*200 all 2

[Roger Stafford]

The problem is that you used a 200-element vector Alloc_Sc and I used a three element vector 'a' which is what I thought you wanted. In that case you should use Walter's solution. You erred in applying his method by using "length(randperm(Alloc_Sc))" instead of "randperm(length(Alloc_Sc))".

[Hamid Reza Barzegar]

even when i do Walter's solution i get this error Error using randperm Size inputs must be scalar.

My code is like this:

     first=100;
     Second=50;
     Third=50;
     Alloc_Sc=[2*ones(1,first),ones(1,Second),-1*ones(1,Third)];
     Alloc_Sc2=length(randperm(Alloc_Sc));
i want to spread Alloc_Sc in random position not all 2 in first and then all Second and finally all Third.

[Roger Stafford]

As I state above, your expression is in error in using "length(randperm(Alloc_Sc))" instead of "randperm(length(Alloc_Sc))".

[Hamid Reza Barzegar]

Thanks for your reply i changed as you mentioned but the data is returned is number between 1 to 200 not my data now there is no error but not my data

first=100;
     Second=50;
     Third=50;
     Alloc_Sc=[2*ones(1,first),ones(1,Second),-1*ones(1,Third)];
     Alloc_Sc2=randperm(length(Alloc_Sc));