Find the closest data point between 2 files by comparing one 3D data point in a file to all 3D data points in another file

Hello

Can anyone please help me with this:

I need to compare two files and find the closest x, y, z coordinates for a file A compared to all the points in B

I have 2 files A=> 6982x3 double

First three columns are x, y, z coordinates

part of file A =

50 -4 -46

50 -2 -46

50 0 -46

54 -6 -44

52 -6 -44

50 -6 -44

B=> 751728x4 double

First three columns are x, y, z coordinates , 4th column region information

part of file B =

33 -6 -51 172

-35 -5 -51 172

-34 -5 -51 172

-33 -5 -51 172

33 -5 -51 172

34 -5 -51 172

I need to have something like this fileA coordinates; region info corresponding to closest coordinate; closest coordinate in the File B

I tried this:

D=[]

for i = 1:size(A,1)

M =[A(i,1),A(i,2),A(i,3)];

Mindist=[];

for j = 1:size(HCP,1)

N= [HCP(j,1),HCP(j,2),HCP(j,3)];

distance = sqrt(sum(((M-N).^2),2));

N=[M,distance,HCP(j,4),N];

Mindist=[Mindist;N];

end

[value,ind]= min(Mindist(:,4));

D=[D;Mindist(ind,:)];

end

But I ran into memory issues

then tried :

distances = pdist2(A(:, 1:3), B(:, 1:3));

I got distances matrix but not exactly as what I want, this only gives me pairwise distances.

I am new to matlab can youplease help me with this

Answer 1

[KSSV]

Read about knnsearch. This is your function.

[Priyanka Gorijala]

Thanks for reply,

I tried this seems to work.

[KSSV]

Not seems....it will work.