MATLAB: Hi everyone , how can I built a matrix of circularly shifted array in efficient way

arraycircshiftMATLAB

I have a given initial array of length M , I want to built a matrix of MxM , by circularly shifting this array, example
for array=[2,0,0] the matrix should be matrix=[2,0,0;0,2,0;0,0,2]
my code works but it not efficient for large M I would be happy if someone can gives me an efficient suggestion
my code:
array=[2,0,0]; % given Initial array
M=length(array);
mat=zeros(M,M);%matrix
mat(1,:)=array;
for i=2:M
array=circshift(array(1,1:M),[0 1]);
mat(i,:)=array;
end

Best Answer

Multiple circshift calls in a loop is not required. One call to toeplitz is simpler:
>> V = [2,0,0];
>> toeplitz(V([1,end:-1:2]),V)
ans =
   2   0   0
   0   2   0
   0   0   2
Or a clearer example:
>> V = [4,3,2,1,0];
>> toeplitz(V([1,end:-1:2]),V)
ans =
   4   3   2   1   0
   0   4   3   2   1
   1   0   4   3   2
   2   1   0   4   3
   3   2   1   0   4
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