Reply by Priyank Saxena ●July 2, 20012001-07-02
hi Mit,

u can use the following command:

ones(size(A))*diag(min(A)) + rand(size(A))*diag((max(A) - min(A)))

in the second term the "diag((max(A) - min(A)))" scales each column
separately according to the required range.

In the first term "diag(min(A))" adds the required bias.

To use the same for rows use premultiplication instead of post-mult.

-priyank

--- wrote:
> Hi
>
> Given that I have a matrix, say A = [1 2 3; 4 5 6],
> how do I draw new samples over the range of A columns using uniform
> distribution?
>
> For example, min(:,1) = 1 and max(:,1) = 4
> Therefore my new sample can have data points ranging from 1 to 4 in
> the first column, and so on. I know I can use rand to draw random
> numbers that is uniformly distributed, but I do not know how to set a
> range for each column of the matrix.
>
> I would really appreciate any help given. Thank you very much in
> advance.
>
> Sincerely
> Mit >
>


__________________________________________________

Reply by ●July 2, 20012001-07-02


First, create a matrix B having enough random numbers (distributed between 0 and
1.0). I'm doing 100 per column:

M = 100;
N = size(A,2);
B = rand(M,N);

Now multiply each column of B by the range indicated by the columns of A:

B = B*diag( A(2,:) - A(1,:) );

Now the random numbers in the jth column of B are from 0 to (A(2,j) - A(1,j)).
This is the correct differential range, but since the range should actually be
A(1,j) to A(2,j), we must move the range up by A(1,j).

B = B + ones(M,1)*A(1,:)

B should now be your desired matrix. Sincerely,
Glen Ragan



Reply by ●July 2, 20012001-07-02
Hi

Given that I have a matrix, say A = [1 2 3; 4 5 6],
how do I draw new samples over the range of A columns using uniform
distribution?

For example, min(:,1) = 1 and max(:,1) = 4
Therefore my new sample can have data points ranging from 1 to 4 in
the first column, and so on. I know I can use rand to draw random
numbers that is uniformly distributed, but I do not know how to set a
range for each column of the matrix.

I would really appreciate any help given. Thank you very much in
advance.

Sincerely
Mit