[Zero-Dim] support input 0D Tensor for std/var

python/paddle/fluid/tests/unittests/test_zero_dim_tensor.py

@@ -854,6 +854,30 @@ def test_mode(self):
             self.assertEqual(x.grad.shape, [])
             self.assertTrue(x.grad.numpy() == 1)
 
+    def test_std(self):
+        x = paddle.full([], 1, 'float32')
+        x.stop_gradient = False
+        out = paddle.std(x)
+        out.backward()
+
+        # checkout shape of out
+        self.assertEqual(out.shape, [])
+
+        # checkout value of out
+        self.assertEqual(out, 0)
+
+    def test_var(self):
+        x = paddle.full([], 1, 'float32')
+        x.stop_gradient = False
+        out = paddle.var(x)
+        out.backward()
+
+        # checkout shape of out
+        self.assertEqual(out.shape, [])
+
+        # checkout value of out
+        self.assertEqual(out, 0)
+
     def test_flatten(self):
         x = paddle.rand([])
         x.stop_gradient = False
@@ -1472,6 +1496,26 @@ def test_mode(self):
         self.assertEqual(res[2].shape, ())
         self.assertTrue(res[2] == 1.0)
 
+    @prog_scope()
+    def test_std(self):
+        x = paddle.full([], 1, 'float32')
+        out = paddle.std(x)
+        paddle.static.append_backward(out)
+
+        prog = paddle.static.default_main_program()
+        res = self.exe.run(prog, fetch_list=[out])
+        self.assertEqual(res[0].shape, (1,))
+
+    @prog_scope()
+    def test_var(self):
+        x = paddle.full([], 1, 'float32')
+        out = paddle.var(x)
+        paddle.static.append_backward(out)
+
+        prog = paddle.static.default_main_program()
+        res = self.exe.run(prog, fetch_list=[out])
+        self.assertEqual(res[0].shape, (1,))
+
     @prog_scope()
     def test_flatten(self):
         x = paddle.full([], 1, 'float32')