Mapping 2 vectors – help to vectorize

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Oh! One other option: since you’re looking for close correspondences between two sorted lists, you could go through them both simultaneously, using a merge-like algorithm. This should be O(max(length(xm), length(xn)))-ish.


match_for_xn = zeros(length(xn), 1);
last_M = 1;
for N = 1:length(xn)
  % search through M until we find a match.
  for M = last_M:length(xm)
    dist_to_curr = abs(xm(M) - xn(N));
    dist_to_next = abs(xm(M+1) - xn(N));

    if dist_to_next > dist_to_curr
      match_for_xn(N) = M;
      last_M = M;
      break
    else
      continue
    end

  end % M
end % N

EDIT:
See @yuk’s comment, the above code is not totally correct!

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