VECTOR_L2

Returns the Euclidean, or L2, distance between two n-dimensional vectors.

Behavior type

Syntax

VECTOR_L2( vector_arr1, vector_arr2 )

Arguments

vector_arr1: N-dimensional vector, type ARRAY of INT, FLOAT, NUMERIC
vector_arr2: N-dimensional vector, type ARRAY of INT, FLOAT, NUMERIC

Note

NULL and NaN values are treated equivalently. If any element in the input array is NULL or NaN, the function returns NULL.

Returns

FLOAT

Examples

The following example computes the distance for two vector arrays:

SELECT id, vector_arr1, vector_arr2, VECTOR_L2(vector_arr1, vector_arr2) AS distance FROM vectors_array;
id |  vector_arr1  |  vector_arr2  |     distance     
----+---------------+---------------+------------------
  1 | [1.0,2.0,3.0] | [4.0,5.0,6.0] | 5.19615242270663
  2 | [1.5,2.5,3.5] | [4.5,5.5,6.5] | 5.19615242270663
  3 | [0.0,1.0,0.0] | [0.0,0.0,1.0] |  1.4142135623731
  4 | [2.0,0.0,0.0] | [0.0,2.0,0.0] | 2.82842712474619
  5 | [1.0,1.0,1.0] | [1.0,1.0,1.0] |                0
(5 rows)

The following example computes the distance between two 5D vectors:

SELECT VECTOR_L2(Array[1.0, 2.0, 3.0, 4.0, 5.0], Array[1.0, 2.0, 3.0, 3.0, 4.0]);
VECTOR_L2 
-----------------
1.4142135623731
(1 row)