add more promotion testing

apex/amp/test/test_promotion.py

@@ -17,18 +17,27 @@ class TestPromotion(unittest.TestCase):
     def tearDown(self):
         self.handle._deactivate()
 
-    def run_binary_promote_test(self, fns, input_shape):
+    def run_binary_promote_test(self, fns, input_shape, x_inplace=False):
         type_pairs = it.product(DTYPES, DTYPES)
         for fn, (xtype, ytype) in it.product(fns, type_pairs):
             x = torch.randn(input_shape, dtype=xtype).requires_grad_()
+            x_leaf = x
+            if x_inplace:
+                # We need a non-leaf to call in place on
+                x = x.clone()
             y = torch.randn(input_shape, dtype=ytype)
             out = fn(x, y)
-            if xtype == torch.float or ytype == torch.float:
-                self.assertEqual(out.type(), FLOAT)
+            if x_inplace:
+                # In place: always match xtype
+                self.assertEqual(out.type(), x.type())
             else:
-                self.assertEqual(out.type(), HALF)
+                # Out of place: match widest type
+                if xtype == torch.float or ytype == torch.float:
+                    self.assertEqual(out.type(), FLOAT)
+                else:
+                    self.assertEqual(out.type(), HALF)
             out.float().sum().backward()
-            self.assertEqual(x.grad.dtype, xtype)
+            self.assertEqual(x_leaf.grad.dtype, xtype)
 
     def test_atan2_matches_widest(self):
         fns = [lambda x, y : torch.atan2(x, y),
@@ -50,9 +59,17 @@ class TestPromotion(unittest.TestCase):
         out = torch.cat(ys + [x_half])
         self.assertEqual(out.type(), HALF)
 
-    # TODOs:
-    # In-place methods on fp16 are errors for fp32
-    # In-place methods match type of self tensor
+    def test_inplace_exp_is_error_for_half(self):
+        xs = torch.randn(self.b)
+        xs.exp_()
+        self.assertEqual(xs.type(), FLOAT)
+        xs = torch.randn(self.b, dtype=torch.half)
+        with self.assertRaises(NotImplementedError):
+            xs.exp_()
+
+    def test_inplace_add_matches_self(self):
+        fn = lambda x, y: x.add_(y)
+        self.run_binary_promote_test([fn], (self.b,), x_inplace=True)
 
 if __name__ == '__main__':
     unittest.main()