Added fromMap constructor to SparseVector

pgvector · Sep 10, 2024 · a48fea5 · a48fea5
1 parent cfab8e6
commit a48fea5
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diff --git a/lib/src/sparsevec.dart b/lib/src/sparsevec.dart
@@ -22,6 +22,16 @@ class SparseVector {
     return SparseVector._(dimensions, indices, values);
   }
 
+  factory SparseVector.fromMap(Map<int, double> map, int dimensions) {
+    var elements = map.entries.where((v) => v.value != 0).toList();
+    elements.sort((a, b) => a.key.compareTo(b.key));
+
+    var indices = elements.map((v) => v.key).toList();
+    var values = elements.map((v) => v.value).toList();
+
+    return SparseVector._(dimensions, indices, values);
+  }
+
   factory SparseVector.fromBinary(Uint8List bytes) {
     var buf = new ByteData.view(bytes.buffer, bytes.offsetInBytes);
     var dimensions = buf.getInt32(0);

diff --git a/test/sparsevec_test.dart b/test/sparsevec_test.dart
@@ -10,4 +10,13 @@ void main() {
     expect(vec.indices, equals([0, 2, 4]));
     expect(vec.values, equals([1, 2, 3]));
   });
+
+  test('fromMap', () {
+    var vec = SparseVector.fromMap({2: 2.0, 4: 3.0, 0: 1.0, 3: 0.0}, 6);
+    expect(vec.toString(), equals('{1:1.0,3:2.0,5:3.0}/6'));
+    expect(vec.toList(), equals([1, 0, 2, 0, 3, 0]));
+    expect(vec.dimensions, equals(6));
+    expect(vec.indices, equals([0, 2, 4]));
+    expect(vec.values, equals([1, 2, 3]));
+  });
 }