Question

In matlab, I am trying to get a matrix M which is 4x50, in which each column stores the four nearest neighbors to the point. I am having trouble computing the nearest neighbor from my 50x50 distance matrix.

other info. Xmat = 3000x50 , K =4 , M is suppose to be 4x50 and D is 50x50.

Editor-S:\MATLAB\Project388.m Project388.mX 63 Write your own code here 64 65 each column stores the K nearest neighbours for that data point 66 67 zeros (K, Nsamples) zeros (Nsamples, Nsamples); M = 68 69 L Lsorted = sort (L); 70 zeros (K, K); 71- Xnhbr Xnhbrindex = zeros (K, Nsamples) 72 73 동10op 74 for i 1: Nsamples 75 for j= 1: Nsamples 76 77 difference 78 Computing the = norm (Xmat (:,i) - Xmat (:,j)); L (i,j) 79 i, sort Ls tec 80 Xnhbr ,i) = Lsorted (2,2:5) Xnhbrindex ,i) 81 = Lsorted (1,2:5).'; 82 83 ij+1 84 end 85 i-i+ 1; 86 end 87 88 Command Window

Answer 1

I am giving an example with sample input of less number of rows and columns to find k nearest neighbours

A=[1 2 1;3 4 1;5 6 1;];

B=[11 12 2;13 4 2;15 16 2;17 18 2;1 2 2;3 4 2;5 6 2;];

[row,col]=size(A); // to get row and column lengths of A

[row1,col1]=size(B); // to get row and column lengths of B

dist=zeros(row,row1); // to set the distance value to find the nearest neighbour i.e., shortest distance

nnarray = zeros(row,row1);

k=5;

nnarray1 = zeros(row,k);

for i=1:row

for j=1:row1

dist(i,j)=sqrt(sum((A(i,:)-B(j,:)).^2)); // the shortest distance

end

[y,index]=sort(dist(i,:)); // store that index into the matrix

nnarray(i,:)=index';

end

// the above program give results of a k^th neighbour of matrix A with respect to matrix B.

the output is the nearest neighbours of matrix A

5 6 7 2 1 3 4

6 5 7 2 1 3 4

7 6 5 2 1 3 4

use this program to get nearest neighbour of any value of K for your inputs