How do I replace the zeros in a matrix with another integer, or with a pos or neg infinity?

I have a 145x145 distance matrix where: (1,1)=0 (2,2)=0 ... Can I replace just the diagonal with infinity values? There are other zeros in the matrix, but I may or may not want to keep those. Is there a process that could replace this diagonal of all zeros with a diagonal of all infinities?

thanx

Answer 1

[Matt Fig]

To replace only the diagonal of a N-by-N matrix with infinity, do:

A(1:N+1:N^2) = inf;  % or A(1:N+1:end)...

If you want to replace all of the zeros in an array with infinity, do:

A(~A) = inf;  % Or A(A==0) = inf;