Comparing two Matrix for similar elements
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suppose you run a check between two matrix, like c=0; if A(1,1) == B (1, 1:3) c=c+1; else c=0; end and the output(ans) is (true, true, false) , I mean (1 1 0).
my counter(c) should run twice(if if A(1,1), B(1,1) and B(1,2) is equal to 8) but it will show c=0. I need C = 2
Other way I found is - Count only when it is true, like
if A(1,1) == B(1,1) c=c+1; else c=0; end
but in the second case, i have to do it for all B elements, and that's not good for big matrix. how to check and count?
2 comentarios
Jan
el 24 de Mayo de 2017
The question is not clear:
c=0;
if A(1,1) == B (1, 1:3)
c=c+1;
else
c=0;
end
Note that A(1,1) == B (1, 1:3) replies a vector, but if requires a scalar condition. Therefore Matlab inserts an all() implicitely.
and the output(ans) is (true, true, false) , I mean (1 1 0).
The shown code does not have any output. It replies either c=1 or c=0, but not [1,1,0].
my counter(c) should run twice(if if A(1,1), B(1,1) and B(1,2)
is equal to 8)
I cannot folow you here.
Respuestas (2)
Andrei Bobrov
el 24 de Mayo de 2017
Editada: Andrei Bobrov
el 24 de Mayo de 2017
c = nnz(A(:)' == B(:)); % MATLAB >= R2016b
c = nnz(bsxfun(@eq, A(:)', B(:))); % MATLAB <= R2016a
3 comentarios
Walter Roberson
el 6 de Dic. de 2019
Only in the sense that some objects cannot be compared. For example if A is object class tf (transfer function) and B is object class primitive chart line, then you would get an error message. But the code would be fine with A being double and B being character for example.
The original question implied that the array sizes are not the same, so the code should not be checking that they are the same.
Daniel Brower
el 6 de Dic. de 2019
I mean if A is an nxn matrix of real numbers and B is an nxn matrix of real numbers, how would I check if A and B are similar matrices to each other, in the sense that B=S^-1*A*S.
Jan
el 24 de Mayo de 2017
Editada: Jan
el 24 de Mayo de 2017
Does only A(1,1) occur in your porblem? Then:
c = (A(1,1) == B)
or if the number of equal elements is wanted
c = sum(A(1,1) == B) % or nnz() instead of sum()
If all elements of A are concerned, see either Andrei's solution, or:
c = sum(ismember(A(:), B(:)) % Or B(:), A(:) ?
2 comentarios
Zeina Abdullah
el 5 de En. de 2022
@Jan can you help me by answer my question in my profile please . i am tring to find similar problem but I did not find
Walter Roberson
el 6 de En. de 2022
https://www.mathworks.com/matlabcentral/answers/1623080-how-to-find-relationship-between-two-or-more-matrix?s_tid=srchtitle appears to be the reference
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