Euclidean distance of two vectors

Asked by bala k on 9 Mar 2011

Latest activity Edited by MathWorks Support Team on 8 Nov 2018

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Euclidean distance of two vector. I have the two image values G=[1x72] and G1 = [1x72]. I need to calculate the two image distance value.

1 Comments

juit on 23 Dec 2016

i have three points a(x1,y1) b(x2,y2) c(x3,y3) i have calculated euclidean distance d1 between a and b and euclidean distance d2 between b and c. if now i just want to travel through a path like from a to b and then b to c. can i add d1 and d2 to calculate total distance traveled by me???

1 Answers

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Answer by Jan on 9 Mar 2011

Edited by Jan on 16 Apr 2016

Accepted Answer

Do you know the definition of the Euclidean distance?

G  = rand(1, 72);
G2 = rand(1, 72);
D  = sqrt(sum((G - G2) .^ 2));

A more efficient method, but this matters only for much larger vectors:

V = G - G2;
D = sqrt(V * V');

Or a Matlab command:

D = norm(G - G2);

A fast C-Mex function: http://www.mathworks.com/matlabcentral/fileexchange/29035-dnorm2

D = DNorm2(G - G2);

Search in the documentation before asking in MATLAB Answers:

docsearch euclidean

7 Comments

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Jared Willard on 2 Oct 2017

I don't know about others but I am getting entirely different results when comparing

D = sqrt(sum((G - G2) .^ 2));

and

D = norm(G - G2);

James Tursa on 2 Oct 2017

What are your G and G2 sizes? Are they real or complex?

Jan on 2 Oct 2017

@Jared: Please mention any details. What is the size and contents of your G and G2 variables? Check if your have redefined sqrt, sum or norm. Try:

format long g
clear variables
G  = rand(1, 72);
G2 = rand(1, 72);
D1 = sqrt(sum((G - G2) .^ 2))
V  = G - G2;
D2 = sqrt(V * V')
D3 = norm(G - G2)

Looks fine. And of course: The formulas are identical from a mathematical point of view. Then I'm sure you have overseen a detail in your comparison.

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bala k (view profile)