fix bug in cosine distance

Author: sivukhin

libsql-sqlite3/src/vector.c

@@ -538,22 +538,7 @@ void vectorSerializeWithMeta(
     return;
   }
 
-  switch (pVector->type) {
-    case VECTOR_TYPE_FLOAT32:
-      vectorF32SerializeToBlob(pVector, pBlob, nDataSize);
-      break;
-    case VECTOR_TYPE_FLOAT64:
-      vectorF64SerializeToBlob(pVector, pBlob, nDataSize);
-      break;
-    case VECTOR_TYPE_FLOAT1BIT:
-      vector1BitSerializeToBlob(pVector, pBlob, nDataSize);
-      break;
-    case VECTOR_TYPE_FLOAT8:
-      vectorF8SerializeToBlob(pVector, pBlob, nDataSize);
-      break;
-    default:
-      assert(0);
-  }
+  vectorSerializeToBlob(pVector, pBlob, nDataSize);
   vectorSerializeMeta(pVector, nDataSize, pBlob, nBlobSize);
   sqlite3_result_blob(context, (char*)pBlob, nBlobSize, sqlite3_free);
 }
@@ -569,6 +554,9 @@ void vectorSerializeToBlob(const Vector *pVector, unsigned char *pBlob, size_t n
     case VECTOR_TYPE_FLOAT1BIT:
       vector1BitSerializeToBlob(pVector, pBlob, nBlobSize);
       break;
+    case VECTOR_TYPE_FLOAT8:
+      vectorF8SerializeToBlob(pVector, pBlob, nBlobSize);
+      break;
     default:
       assert(0);
   }

libsql-sqlite3/src/vectorfloat8.c

@@ -100,10 +100,10 @@ float vectorF8DistanceCos(const Vector *v1, const Vector *v2){
   assert( v2->type == VECTOR_TYPE_FLOAT8 );
 
   vectorF8GetParameters(v1->data, v1->dims, &alpha1, &shift1);
-  vectorF8GetParameters(v2->data, v1->dims, &alpha2, &shift2);
+  vectorF8GetParameters(v2->data, v2->dims, &alpha2, &shift2);
 
   /*
-   * (Ax + S)^2 = A^2 x^2 + S^2 + 2AS x -> we need to maintain 'sumsq' and 'sum'
+   * (Ax + S)^2 = A^2 x^2 + 2AS x + S^2 -> we need to maintain 'sumsq' and 'sum'
    * (A1x + S1) * (A2y + S2) = A1A2 xy + A1 S2 x + A2 S1 y + S1 S2 -> we need to maintain 'dot' and 'sum' again
   */
 
@@ -112,12 +112,12 @@ float vectorF8DistanceCos(const Vector *v1, const Vector *v2){
     sum2 += data2[i];
     sumsq1 += data1[i]*data1[i];
     sumsq2 += data2[i]*data2[i];
-    doti += data1[i] * data2[i];
+    doti += data1[i]*data2[i];
   }
 
-  dot = alpha1 * alpha2 * (float)doti + alpha1 * shift2 * (float)sum1 + alpha2 * shift1 * (float)sum2 + shift1 * shift2;
-  norm1 = alpha1 * alpha1 * (float)sumsq1 + 2 * alpha1 * shift1 * (float)sum1 + shift1 * shift1;
-  norm2 = alpha2 * alpha2 * (float)sumsq2 + 2 * alpha2 * shift2 * (float)sum2 + shift2 * shift2;
+  dot = alpha1 * alpha2 * (float)doti + alpha1 * shift2 * (float)sum1 + alpha2 * shift1 * (float)sum2 + shift1 * shift2 * v1->dims;
+  norm1 = alpha1 * alpha1 * (float)sumsq1 + 2 * alpha1 * shift1 * (float)sum1 + shift1 * shift1 * v1->dims;
+  norm2 = alpha2 * alpha2 * (float)sumsq2 + 2 * alpha2 * shift2 * (float)sum2 + shift2 * shift2 * v1->dims;
 
   return 1.0 - (dot / sqrt(norm1 * norm2));
 }

libsql-sqlite3/test/libsql_vector.test

@@ -80,9 +80,10 @@ do_execsql_test vector-1-func-valid {
   {2.0}
   {1.0}
   {0.0}
-  {-1.22070709096533e-08} {0.0}
-  {1.54134213516954e-05} {0.000117244853754528}
-  {-0.297326117753983} {0.0582110174000263}
+
+  {-6.10352568486405e-09} {0.0}
+  {0.000111237335659098} {0.000117244853754528}
+  {0.0576796568930149} {0.0582110174000263}
 }
 
 do_execsql_test vector-1-conversion {