Find common non-zero indexes

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Tha saliem 2017-6-10

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https://ww2.mathworks.cn/matlabcentral/answers/344168-find-common-non-zero-indexes

评论： Andrei Bobrov 2017-6-12

采纳的回答： Andrei Bobrov

在 MATLAB Online 中打开

i have a matrix like this:

A=[4,0,5,5;0,2,4,0;3,0,0,0;0,1,0,3;3,0,1,0;2,0,0,2;0,0,3,0;2,3,4,0]

And matrix B and C are row numbers derived from matrix A based on some condition.

    B=[7;8]
    C=[1;2;3;4;5;6]

I want to compare values of matrix B with each value of matrix C and find what nonzero indexes are common between both in matrix A.

for example: first value of B is 7 and it will be compared with all values of C. In first iteration, comparison will be 7 and 1 and result will be 3 because 3rd value is common nonzero value between both. Similarly:

    result(7,2)=3
    result(7,3)=0 (No nonzero index is common)

and similarly after 7, 8 will be compared with all values of C.

Please help on this.

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Tha saliem 2017-6-10

Also it is not necessary that values in B and C are sorted. It can be in any order

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采纳的回答

Andrei Bobrov 2017-6-10

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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/344168-find-common-non-zero-indexes#answer_270267

编辑：Andrei Bobrov 2017-6-12

在 MATLAB Online 中打开

[EDIT 2]

A=[4,0,5,5;0,2,4,0;3,0,0,0;0,1,0,3;3,0,1,0;2,0,0,2;0,0,3,0;2,3,4,0];
B=[7;8];
[C,~] = find(bsxfun(@ne,(1:size(A,1))',B(:)'));
n = numel(B);
B1 = repelem(B,numel(C)/n);
k = squeeze(num2cell(  bsxfun(@times,bsxfun(@and,A(C,:), A(B1,:)),1:size(A,2)),2 ));
result = cellfun(@nonzeros,k,'un',0);
result(cellfun(@isempty,result)) = {0}
result = reshape(result,[],n);