MATLAB: How to create this specified matrix

specific matrix create

Hi all. I have some values from U(1)…to…U(500) , and I need help to create this matrix:

Best Answer

One fast and easy way is to use toeplitz, it only needs one line of code:

>> U = 1:9;
>> toeplitz(U,[U(1),zeros(1,numel(U)-1)])
ans =
     1     0     0     0     0     0     0     0     0
     2     1     0     0     0     0     0     0     0
     3     2     1     0     0     0     0     0     0
     4     3     2     1     0     0     0     0     0
     5     4     3     2     1     0     0     0     0
     6     5     4     3     2     1     0     0     0
     7     6     5     4     3     2     1     0     0
     8     7     6     5     4     3     2     1     0
     9     8     7     6     5     4     3     2     1

tril(toeplitz(U))

Related Solutions

MATLAB: How can i avoid the for loop in this case

Method one: logical equals:

>> a = [3,6,7,8];
>> V = 1:10;
>> M = double(V(:)==a) % requires MATLAB >= R2016b
M =
   0   0   0   0
   0   0   0   0
   1   0   0   0
   0   0   0   0
   0   0   0   0
   0   1   0   0
   0   0   1   0
   0   0   0   1
   0   0   0   0
   0   0   0   0

For earlier MATLAB versions replace == with bsxfun.

Method two: sub2ind:

>> M = zeros(10,4);
>> X = sub2ind(size(M),a,1:4);
>> M(X) = 1
M =
   0   0   0   0
   0   0   0   0
   1   0   0   0
   0   0   0   0
   0   0   0   0
   0   1   0   0
   0   0   1   0
   0   0   0   1
   0   0   0   0
   0   0   0   0

MATLAB: How to create a lower triangle matrix from a single column matrix.

tril(toeplitz(A))

is an option

Best Answer

Related Solutions

MATLAB: How can i avoid the for loop in this case

MATLAB: How to create a lower triangle matrix from a single column matrix.

Related Question