User defined distance function

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MByk
MByk on 2 Jul 2017
Commented: MByk on 2 Jul 2017
I'am trying to calculate Canberra distance (formula of the Canberra distance sum(a-b/|a|+|b|)) by defining a custom distance function but it is not working correctly. Would you help correcting my function? Thank you.
r = [0 3 4 5;7 6 3 -1;-1 1 -1 1;2 3 4 5];
dist = squareform(pdist(r,@f))
function dC = f(a,b)
[m,~]=size(b);
for i=1:m
dC = sum(abs(a - b(i,:))./(abs(a) + abs(b(i,:))));
end
end

Accepted Answer

Andrei Bobrov
Andrei Bobrov on 2 Jul 2017
Edited: Andrei Bobrov on 2 Jul 2017
r = [0 3 4 5;7 6 3 -1;-1 1 -1 1;2 3 4 5];
for MATLAB >= R2016b
dist = squareform(pdist(r,@(a,b)sum(abs(a - b)./(abs(a) + abs(b)),2)))
for MATLAB <= R2016a
f = @(a,b)sum(abs(bsxfun(@minus,a,b))./bsxfun(@plus,abs(a),abs(b)),2);
dist1 = squareform(pdist(r,f))
for your code
dist = squareform(pdist(r,@f))
function dC = f2(a,b)
[m,~] = size(b);
dC = zeros(m,1);
for ii=1:m
dC(ii) = sum(abs(a - b(ii,:))./(abs(a) + abs(b(ii,:))));
end
end
  1 Comment
MByk
MByk on 2 Jul 2017
Thank you very much, it is working now. Much appreciated.

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