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find the distance from each point in matrix B to all point in matrix A

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ha ha
ha ha on 26 Oct 2017
Commented: Rik on 27 Oct 2017
Let's say: I have the matrix A containing of 5 points
A=[ 5 5 1 ----> coordinate (x,y,z) of point A1
4 5 2 ----> coordinate (x,y,z) of point A2
1 1 1 ----> coordinate (x,y,z) of point A3
2 3 1 ----> coordinate (x,y,z) of point A4
6 1 7 ] ----> coordinate (x,y,z) of point A5
And, I also have matrix B:
B=[ 0 2 1 ----> coordinate (x,y,z) of point B1
4 1 1 ] ----> coordinate (x,y,z) of point B2
How to find the Euclidean distance between each point in B and all points(1,2,3,4,5) in A.
Example:
distance between point B1 and points A1:
=sqrt{(5-0)^2+ (5-2)^2 + (1-1)^2}= 5.83
distance between point B1 and points A2
distance between point B1 and points A3
.......................................
distance between point B2 and points A1
distance between point B2 and points A2, A3,A4, A5
*I hope the result will be shown in matrix C(2-by-5)*
  1 Comment
Rik
Rik on 26 Oct 2017
Knowing my answer on your previous question, what do you think would be the solution? It isn't that hard. Of course you could solve this with a loop, but there is a direct solution, for which you can use functions like repmat.
Show some effort.

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Accepted Answer

Andrei Bobrov
Andrei Bobrov on 26 Oct 2017
Edited: Andrei Bobrov on 26 Oct 2017
Or
Dista = squeeze(sqrt(sum((A - reshape(B',1,3,[])).^2,2))); % New MATLAB
Dista = squeeze(sqrt(sum(bsxfun(@minus,A,reshape(B',1,3,[])).^2,2))); % Old MATLAB

More Answers (1)

KSSV
KSSV on 26 Oct 2017
doc pdist and pdist2.
  4 Comments
Rik
Rik on 27 Oct 2017
Typing doc pdist will open the documentation for the pdist function, which you can also find online. If you look at the 'see also' section, you will a find reference to the pdist2 function.
Knowing how to look for and read the documentation is a very useful skill. Extremely easy to learn, sometimes hard to master. Using your favorite internet search engine also helps out a lot.

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