Fix scalar check for sparse tensors. (#8197)

zou3519 · web-flow · commit 115a494b5f00 · 2018-06-06T12:24:25.000-04:00
* Fix scalar check for sparse tensors. As discovered in #8152 If `t` is a scalar sparse tensor, `t._indices` used to return a sparse empty tensor because the scalar check was incorrect. This PR modifies the scalar check to return a dense tensor instead of a sparse tensor. i.e. ``` tensor = torch.sparse_coo_tensor([], [], torch.Size([]), device=device) out = tensor._indices() # was a sparse tensor, now is dense. ``` * Fix typos
diff --git a/aten/src/ATen/Declarations.cwrap b/aten/src/ATen/Declarations.cwrap
@@ -3885,7 +3885,7 @@
   aten_custom_call: |
     if (self_->isScalar()) {
       // Empty tensor
-      return self_->type().toScalarType(kLong).tensor({0});
+      return toBackend(toDense(backend())).toScalarType(kLong).tensor({0});
     }
 ]]
 
diff --git a/test/test_sparse.py b/test/test_sparse.py
@@ -910,6 +910,12 @@ def test_factory_size_check(self):
         with self.assertRaisesRegex(RuntimeError, "values and sizes are inconsistent"):
             self.SparseTensor(indices, values, sizes)
 
+    def test_factory_empty_indices(self):
+        device = 'cuda' if self.is_cuda else 'cpu'
+        tensor = torch.sparse_coo_tensor([], [], torch.Size([]), device=device)
+        expected_indices = torch.tensor([], dtype=torch.long, device=device)
+        self.assertEqual(tensor._indices(), expected_indices)
+
     @cpu_only
     def test_factory_type_inference(self):
         t = torch.sparse_coo_tensor(torch.tensor(([0], [2])), torch.tensor([1.], dtype=torch.float32))

Original file line number	Diff line number	Diff line change
`@@ -3885,7 +3885,7 @@`
`3885`	`3885`	`aten_custom_call: \|`
`3886`	`3886`	`if (self_->isScalar()) {`
`3887`	`3887`	`// Empty tensor`
`3888`		`- return self_->type().toScalarType(kLong).tensor({0});`
	`3888`	`+ return toBackend(toDense(backend())).toScalarType(kLong).tensor({0});`
`3889`	`3889`	`}`
`3890`	`3890`	`]]`
`3891`	`3891`