How to use intersect command with a tolerance value?
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I have two vector with different lenght and I want to compare the values of the vectors one by one with a certain tolerance because the numbers are similar but not equal, e.g. 222.456 and 222.389. I was using the command intersect but it only gives me the numbers that are exactly the same.
Answers (1)
Jan
on 12 Feb 2019
Edited: Jan
on 15 Feb 2019
While ismembertol might be useful, I'm still puzzled by the way it defines the tolerance.
If the vectors are not too large (some thousand elements should be fine), a simple loop approach should be sufficient:
function [AI, BI] = CommonElemTol(A, B, Tol)
A = A(:);
B = B(:);
nA = numel(A);
M = zeros(1, nA);
% Collect the index of the first occurrence in B for every A:
for iA = 1:nA
dist = abs(A(iA) - B); % EDITED: Of course abs() is needed
Ind = find(dist < Tol, 1); % Absolute tolerance
% Ind = find(dist ./ A(iA) < Tol, 1); % Relative tolerance
if ~isempty(Ind)
M(iA) = Ind;
end
end
AI = find(M); % If any occurrence was found, this A exists
if isempty(AI) % prevent: Empty matrix: 0-by-1
AI = [];
end
BI = M(AI); % at this index in B
end
3 Comments
Stephen23
on 15 Feb 2019
I suspect that
dist = (A(iA) - B);
should be
dist = abs(A(iA) - B);
otherwise there is no absolute involved.
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