Added sample_indices api to virtual tensors. (#2654)

* Added sample_indices() to virtual tensor and dataset.

* Added test.

* Fixed test for old libdeeplake. Need to revisit after libdeeplake release.

* Added more tests.

deeplake/core/dataset/deeplake_query_dataset.py

@@ -284,6 +284,15 @@ def no_view_dataset(self):
     def index(self):
         return self._index
 
+    @property
+    def sample_indices(self):
+        for t in self.tensors.values():
+            try:
+                return t.indra_tensor.indexes
+            except RuntimeError:
+                pass
+        return range(self.num_samples)
+
     def _tensors(
         self, include_hidden: bool = True, include_disabled=True
     ) -> Dict[str, Tensor]:

deeplake/core/dataset/deeplake_query_tensor.py

@@ -137,6 +137,13 @@ def min_shape(self):
     def chunk_engine(self):
         raise NotImplementedError("Virtual tensor does not have chunk engine.")
 
+    @property
+    def sample_indices(self):
+        try:
+            return self.indra_tensor.indexes
+        except RuntimeError:
+            return range(self.num_samples)
+
     @property
     def shape(self):
         if (

deeplake/core/tests/test_deeplake_indra_dataset.py

@@ -423,3 +423,19 @@ def test_virtual_tensors(local_auth_ds_generator):
         assert deeplake_indra_ds.score[100 - i].numpy() == [
             np.sqrt(2.0 / (i + 1) / (i + 1))
         ]
+
+    assert deeplake_indra_ds.sample_indices == slice(0, 100, 1)
+    deeplake_indra_ds = deeplake_ds.query(
+        "SELECT *, l2_norm(embeddings - ARRAY[0, 0, 0]) as score order by l2_norm(embeddings - ARRAY[0, 0, 0]) asc"
+    )
+    assert list(deeplake_indra_ds.sample_indices) == list(reversed(range(100)))
+    assert list(deeplake_indra_ds.embeddings.sample_indices) == list(
+        reversed(range(100))
+    )
+    assert deeplake_indra_ds.score.sample_indices == slice(0, 100, 1)
+
+    deeplake_indra_ds = deeplake_ds.query(
+        "SELECT l2_norm(embeddings - ARRAY[0, 0, 0]) as score order by l2_norm(embeddings - ARRAY[0, 0, 0]) asc"
+    )
+    assert deeplake_indra_ds.sample_indices == slice(0, 100, 1)
+    assert deeplake_indra_ds.score.sample_indices == slice(0, 100, 1)