Create a matrix with rand

I have a

vector = 2*rand(1,3)-1

I want to create a matrix with x lines and columns the vectors.

I have done the following:

x=10;
for i=1:x
  2*rand(1,3)-1
end

But I want to write the loop in another way,in a one line because i want to use that matrix. I tried this:

a=2*rand(1,3)(size(1:x)); % but i can't figure how.

Also, is there a way not to write 2*rand(1,3)-1 all the time?Because, if i write "vector" ,it will keep only one value,it doesn't generate random numbers.

[Todd Flanagan]

George, I moved your reply to a comment in Doug's answer. You may want to accept Doug's answer if it helped you.

Answer 1

[Doug Hull]

You will want to create a function that generates a random vector of the correct size. every time you call the function, a new vector will be created. The way you are doing it now, you are creating one random vector and storing in a variable.

As a point of suggestion, I would not use a variable name of vector. It is just kind of confusing.

function out = randVec

   out = 2*rand(1,3)-1;
>> randVec
ans =
   -0.9286    0.6983    0.8680

>> randVec  
ans =  
    0.3575    0.5155    0.4863

>> randVec  
ans =  
   -0.2155    0.3110   -0.6576

You can now string these together

randMat = [randVec; randVec; randVec; randVec]

A for loop, might be better here.

Of course, if you are going to do this only to make a amtrix, why not:

randMat = 2*rand(4,3)-1;

[Todd Flanagan]

George says, "Hello, Thanks a lot for the answer!

The thing that i wanted was : 2*rand(4,3)-1; ,where 4 is x.

What i was doing was that i wanted to create a matrix from am already "vector" matrix and add there x lines. But the line above does it all!"