How to find the distance between two non-zero (the element is a one) elements in a matrix

I have a matrix with entries as "1" at random places and i need to find (a) find its non-zero neighbours (b) find the euclidean distance between its non-zero neighbours and the pixel itself

Answer 1

[Andrei Bobrov]

use function pdist from Statistics Toolbox

a = rand(10)<.07

[i1 j1] = find(a);
out = tril(ones(numel(i1)),-1)
out(out~=0) = hypot(pdist(i1),pdist(j1))

OR without pdist

[i1 j1] = find(a);
idx = [i1 j1];
ij = arrayfun(@(ii)tril(bsxfun(@minus,idx(:,ii),idx(:,ii).'),-1),1:2,'un',0);
out = hypot(ij{:})

[Bharathwaj]

thanks andrei