To set value based on condition in a matrix

Hi. I have a problem to set up value in a matrix. I have a A=m*n matrix. For example, m=13, and n=7. So, my coding will be like this.

    A=zeros(m,n);

    A=

         0     0     0     0     0     0     0
         0     0     0     0     0     0     0
         0     0     0     0     0     0     0
         0     0     0     0     0     0     0
         0     0     0     0     0     0     0
         0     0     0     0     0     0     0
         0     0     0     0     0     0     0
         0     0     0     0     0     0     0
         0     0     0     0     0     0     0
         0     0     0     0     0     0     0
         0     0     0     0     0     0     0
         0     0     0     0     0     0     0
         0     0     0     0     0     0     0

So, I need to put value x=1 into matrix A based on algorithm as below:

1. x need to appear in every row of matrix A. The outcome will be like as below:

   A=

         1     0     0     0     0     0     0
         0     1     0     0     0     0     0
         0     0     1     0     0     0     0
         0     0     0     1     0     0     0
         0     0     0     0     1     0     0
         0     0     0     0     0     1     0
         0     0     0     0     0     0     1
         1     0     0     0     0     0     0
         0     1     0     0     0     0     0
         0     0     1     0     0     0     0
         0     0     0     1     0     0     0
         0     0     0     0     1     0     0
         0     0     0     0     0     1     0

3. The value of x of first row may start in first column, second column, or any column (random selection), but the value x of the next row is put after one column of previous row. For example, if value x is start in first row in 5 column, the matrix will become like this:

A=

         0     0     0     0     1     0     0
         0     0     0     0     0     1     0
         0     0     0     0     0     0     1
         1     0     0     0     0     0     0
         0     1     0     0     0     0     0
         0     0     1     0     0     0     0
         0     0     0     1     0     0     0
         0     0     0     0     1     0     0
         0     0     0     0     0     1     0
         0     0     0     0     0     0     1
         1     0     0     0     0     0     0
         0     1     0     0     0     0     0
         0     0     1     0     0     0     0

Answer 1

[Andrei Bobrov]

m=13; % [m,n] - size of our matrix
n=7;
i1 = 5;
x = 1;

B = repmat(x*eye(n),2*ceil(m/n),1);
Bout = B(i1:i1+m,:);

[syamil syam]

the answer is very helpful. but how if i want to put one more value like x=1, y= 2 without change the matric size?

[Azzi Abdelmalek]

syamil, this is not your question, because it's posted by Yue in another question. http://www.mathworks.com/matlabcentral/answers/47165-how-to-set-more-than-1-value-to-this-code

Answer 2

[Azzi Abdelmalek]

     x=1;
     n=13,m=7,n1=5 ; A=zeros(n,m);% n1 is your random number 
     A(sum([ 1:n; mod(n1-1:n+n1-2,m)*n]))=x

     %to add another x=2 (for example) with n1=4; repeat 
      x=2;n1=4
      A(sum([ 1:n; mod(n1-1:n+n1-2,m)*n]))=x

[Azzi Abdelmalek]

% you just change the value x and n1;

   x=2;n1=4;  %n1 your another random number
   A(sum([ 1:n; mod(n1-1:n+n1-2,m)*n]))=y

Answer 3

[Matt Fig]

Here is an example.

% First make the matrix and get the needed numbers...
A = zeros(ceil(rand(1,2)*10)+1);   % The matrix, a random size.
[M,N] = size(A);
c = ceil(rand*N); % Starting column in row 1.

% And now for the method....
idx = mod(c:c+M-1,N);
idx(~idx) = N;
A((1:M) + (idx-1)*M) = 1