Is there a way to fill a matrix around the diagonals?

I have a vector that I need to use to fill in the rows of a matrix. This vector will repeat over each row in the matrix except for the indices corresponding to the diagonals. Is there any way to do this without the need of a for loop?

Answer 1

[David Hill]

What are the values for the diagonals? I assume you are talking about a square matrix. The below zeros out the diagonals.

x=repmat(v,length(v),1).*~eye(length(v)).*rot90(~eye(length(v)));

[Sohrab Salimian]

this doesn't quite work,

>> v = [ 1, 2, 4, 5];
>> x=repmat(v,length(v),1).*~eye(length(v)).*rot90(~eye(length(v)))

x =

     0     2     4     0
     1     0     0     5
     1     0     0     5
     0     2     4     0
     
     

I want the vector v to literally fill around the diagonal (the diagonal can be zeros). In here there are missing values in the off diagonals

[Sohrab Salimian]

in the top row for example the values would be [0, 1, 2, 4, 5];

[David Hill]

You are very confusing. You previously said diagonals. Do you just want the main diagonal to be zero?

x=repmat(v,length(v),1).*~eye(length(v));

[Sohrab Salimian]

yes I just want the main diagonal to be zero and the remaining indices to contain the vector v, all the values in v.

[David Hill]

The above should work for you.

[Sohrab Salimian]

thanks