Find the distance from one point in a matrix to all other points in a matrix

Question

I have a matrix a and I want to calculate the distance from one point to all other points. So really the outcome matrix should have a zero (at

Answer 1

IMPORTANT: data_matrix is D X N, where D is number of dimensions and N is number of data points!

final_dist_pairs=data_matrix'*data_matrix;

norms = diag(final_dist_pairs);

final_dist_pairs = bsxfun(@plus, norms, norms') - 2 * final_dist_pairs; Hope it helps!

% Another important thing, Never use pdist function of MATLAB. It is a sequential evaluation, that is something like for loops and takes a lot of time, maybe in O(N^2)