distance and matrix unique numbers
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Could you, guys, help me please. I have a matrix X X =
2.2000 3.3000
2.2000 3.3000
4.0000 5.0000
3.0000 5.0000
I need to get from this [index,A]
index = [2] or equivalently index = [1]
and
A =
2.2000 3.3000
4.0000 5.0000
3.0000 5.0000
Then I need to calculate the distance to the nearest neighbor within that matrix A. i.e. it will be 3x1 vector of distances.
Any help please. Thanks
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Answers (4)
the cyclist
on 29 Sep 2011
I don't really understand the output you want. In the first step, do you just want the unique rows? You can do that with:
>> [uniqueX,i,j] = unique(X,'rows')
Read the help file for the unique() function for more details.
Fangjun Jiang
on 29 Sep 2011
Do you mean this:
X=[2.2000 3.3000
2.2000 3.3000
4.0000 5.0000
3.0000 5.0000];
index=2;
A=X;
A(index,:)=[];
D=dist(A')
Function dist() requires Neural Network Toolbox. You may also check the function pdist(), which requires Statistics Toolbox.
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Walter Roberson
on 29 Sep 2011
2 Comments
Walter Roberson
on 29 Sep 2011
Subtract one of the repeated rows from another: the result will very likely include a non-zero result. Make sure you are using
format long g
as format f might truncate the results.
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