MATLAB: Filling a matrix with a loop

Question

Hi community,

I want to create a large matrix 400×400, In this matrix I want it to have the form

A= [1 1 0 1 000000000000000000……..;0 1 1 0 1 00000000000000……; 0 0 1 1 0 1 00000000000000000] and so on till it is a 400×400 matrix.

I could not find a way yet to easiliy do this. As doing this manually is way too much work.

Does anyone know how to do this?

Answer 1

"Does anyone know how to do this?"

This is simple and efficient with toeplitz:

>> C = [1,zeros(1,399)];
>> R = [1,1,0,1,zeros(1,396)];
>> M = toeplitz(C,R);
>> size(M)
ans =
   400   400
>> M(1:9,1:20) % first rows and columns
ans =
   1   1   0   1   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0
   0   1   1   0   1   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0
   0   0   1   1   0   1   0   0   0   0   0   0   0   0   0   0   0   0   0   0
   0   0   0   1   1   0   1   0   0   0   0   0   0   0   0   0   0   0   0   0
   0   0   0   0   1   1   0   1   0   0   0   0   0   0   0   0   0   0   0   0
   0   0   0   0   0   1   1   0   1   0   0   0   0   0   0   0   0   0   0   0
   0   0   0   0   0   0   1   1   0   1   0   0   0   0   0   0   0   0   0   0
   0   0   0   0   0   0   0   1   1   0   1   0   0   0   0   0   0   0   0   0
   0   0   0   0   0   0   0   0   1   1   0   1   0   0   0   0   0   0   0   0
>> M(392:400,381:400) % last rows and columns
ans =
   0   0   0   0   0   0   0   0   0   0   0   1   1   0   1   0   0   0   0   0
   0   0   0   0   0   0   0   0   0   0   0   0   1   1   0   1   0   0   0   0
   0   0   0   0   0   0   0   0   0   0   0   0   0   1   1   0   1   0   0   0
   0   0   0   0   0   0   0   0   0   0   0   0   0   0   1   1   0   1   0   0
   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   1   1   0   1   0
   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   1   1   0   1
   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   1   1   0
   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   1   1
   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   1