pgvector.git / summary / log / commit / refs

commit    47e5a86b63df816ccfc3d2aacfc277fdfa3aa6e5
Author:   Andrew Kane <andrew@ankane.org>
Date:     Tue Jul 25 21:54:13 2023 +0000

    Fixed out of range results for cosine distance - fixes #196


 CHANGELOG.md                |  1 +
 src/vector.c                | 11 ++++++++++-
 test/expected/functions.out | 12 ++++++++++++
 test/sql/functions.sql      |  2 ++
 4 files changed, 25 insertions(+), 1 deletion(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 4acdfb69..82e589b3 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,6 +5,7 @@
 - Added element-wise multiplication for vectors
 - Added `sum` aggregate
 - Improved performance of distance functions
+- Fixed out of range results for cosine distance
 
 ## 0.4.4 (2023-06-12)
 
diff --git a/src/vector.c b/src/vector.c
index 78dc4e44..6709b0df 100644
--- a/src/vector.c
+++ b/src/vector.c
@@ -630,6 +630,7 @@ cosine_distance(PG_FUNCTION_ARGS)
 	float		distance = 0.0;
 	float		norma = 0.0;
 	float		normb = 0.0;
+	double		similarity;
 
 	CheckDims(a, b);
 
@@ -642,7 +643,15 @@ cosine_distance(PG_FUNCTION_ARGS)
 	}
 
 	/* Use sqrt(a * b) over sqrt(a) * sqrt(b) */
-	PG_RETURN_FLOAT8(1.0 - ((double) distance / sqrt((double) norma * (double) normb)));
+	similarity = (double) distance / sqrt((double) norma * (double) normb);
+
+	/* Keep in range */
+	if (similarity > 1)
+		similarity = 1.0;
+	else if (similarity < -1)
+		similarity = -1.0;
+
+	PG_RETURN_FLOAT8(1.0 - similarity);
 }
 
 /*
diff --git a/test/expected/functions.out b/test/expected/functions.out
index 46bb8fef..268706a8 100644
--- a/test/expected/functions.out
+++ b/test/expected/functions.out
@@ -96,6 +96,18 @@ SELECT cosine_distance('[1,1]', '[-1,-1]');
 
 SELECT cosine_distance('[1,2]', '[3]');
 ERROR:  different vector dimensions 2 and 1
+SELECT cosine_distance(array_fill(0.1, ARRAY[1536])::vector, array_fill(0.111, ARRAY[1536])::vector);
+ cosine_distance 
+-----------------
+               0
+(1 row)
+
+SELECT cosine_distance(array_fill(0.1, ARRAY[1536])::vector, array_fill(-0.111, ARRAY[1536])::vector);
+ cosine_distance 
+-----------------
+               2
+(1 row)
+
 SELECT l1_distance('[0,0]', '[3,4]');
  l1_distance 
 -------------
diff --git a/test/sql/functions.sql b/test/sql/functions.sql
index fa297171..26bf567c 100644
--- a/test/sql/functions.sql
+++ b/test/sql/functions.sql
@@ -24,6 +24,8 @@ SELECT cosine_distance('[1,2]', '[0,0]');
 SELECT cosine_distance('[1,1]', '[1,1]');
 SELECT cosine_distance('[1,1]', '[-1,-1]');
 SELECT cosine_distance('[1,2]', '[3]');
+SELECT cosine_distance(array_fill(0.1, ARRAY[1536])::vector, array_fill(0.111, ARRAY[1536])::vector);
+SELECT cosine_distance(array_fill(0.1, ARRAY[1536])::vector, array_fill(-0.111, ARRAY[1536])::vector);
 
 SELECT l1_distance('[0,0]', '[3,4]');
 SELECT l1_distance('[0,0]', '[0,1]');


[parent: f210791846fd]