find 2 common values of 3 in row matrix?
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HI,
I have a 3 columns and n rows matrix I need to find in this matrix, witch rows own the same 2 values of the 3 as the first row. the values can be in a other column order. then find witch rows own the same 2 values of the 3 as the second row...etc
example: A=[1,2,3;3,2,4;5,6,7;7,6,8]
the first loop must find that row 1 has 2 commun values with row 2. third loop must find that row 3 has 2 commun values with row 4.
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Image Analyst
2015-1-30
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dpb
2015-1-30
>> for i=1:2:size(A,1),cmn=intersect(A(i,:),A(i+1,:)),end
cmn =
2 3
cmn =
6 7
>>
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Stephen23
2015-1-31
Note that i and j should not be used for variable names, as these are both names of the inbuilt imaginary unit .
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dpb
2015-2-2
1) Have you preallocated Qnor? If not, that'll help noticeably if sizes are very large
2) Is this not symmetric in the end? If so, running the loop only over the triangular section would cut it roughly in half. Also, the i==j locations are all identities.
Just one minor syntax that won't have any significant impact on speed would be
if voisins(i,1) ~=0 && voisins(i,2) ~=0 && voisins(i,3) ~=0
can be written as
if all(voisins(i,:))
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