How to use intersect command with a tolerance value?

Question

Vishal Dwivedi 2019-2-12

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/444501-how-to-use-intersect-command-with-a-tolerance-value

评论： Jan 2019-2-15

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.

1 个评论
显示 -1更早的评论隐藏 -1更早的评论

madhan ravi 2019-2-12

perhaps ismembertol() ?

请先登录，再进行评论。

请先登录，再回答此问题。

Answer 1

Jan 2019-2-12

1
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/444501-how-to-use-intersect-command-with-a-tolerance-value#answer_360667

编辑：Jan 2019-2-15

在 MATLAB Online 中打开

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