Computing Euclidean distance between 2 points

I found a code computing Euclidean distance as

diff = q - p;
dist = sqrt(diff * diff');

is there any difference from the standard Euclidean distance formula, why transpose is taken?

Answer 1

[Rik]

By doing a matrix multiplication on a vector, you implicitly take the sum over all elements.

Note that this will only work if both p and q are row vectors.

q=rand(1,5);p=rand(1,5);
diff=q-p;
diff * diff'  ,  sum(diff .* diff)

ans = 0.6624

ans = 0.6624

Answer 2

[Bruno Luong]

For a row vector d

% sum(d.^2) 

is equal to

% d*d'

Example

d=randi(10,1,3)

d = 1×3

9 6 5

sum(d.^2)

ans = 142

d*d'

ans = 142