MATLAB: How to find euclidean distance between one vector and many other vectors

euclidean distance

Hi
I like to calculate Euclidean distance between my first matrix, which contains from one vector, and many other matrices which have similar dimensions ( row vectors ) and determine the smallest distance, and which matrix has it.
Example:
if I have D = [ 1 2 4]
and I1 = [3 5 5 ] , I2 = [ 5 7 8 ], I3 = [ 9 8 7 ] , I4 = [ 1 2 3 ]
so after calculating the Euclidean distance between D AND I1,I2,I3 and I4 the smallest distance will be between D and I4. D as reference
How can I do that????
Thank you

Best Answer

Try pdist2() if you have the Statistics and Machine Learning Toolbox
D = [ 1 2 4]
I1 = [3 5 5 ]
I2 = [5 7 8 ]
I3 = [9 8 7 ]
I4 = [1 2 3 ]
IAll = [I1;I2;I3;I4]
distances = pdist2(D, IAll)
[minDistance, indexOfMinDistance] = min(distances)
You'll see:
D =
1 2 4
I1 =
3 5 5
I2 =
5 7 8
I3 =
9 8 7
I4 =
1 2 3
IAll =
3 5 5
5 7 8
9 8 7
1 2 3
distances =
3.74165738677394 7.54983443527075 10.4403065089106 1
minDistance =
1
indexOfMinDistance =
4
indexOfMinDistance will be 4, and since I put I4 into row 4, I4 has the closest distance to D.
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