fix doc, last iter, and test for amp

python/paddle/hapi/model.py

@@ -1584,7 +1584,9 @@ class Model(object):
             callbacks (Callback|None): A list of `Callback` instances to apply
                 during training. If None, `ProgBarLogger` and `ModelCheckpoint`
                 are automatically inserted. Default: None.
-            accumulate (int): The number of steps to accumulate gradident during training process before optimizer updates. It can mimic large batch size. Default: 1.
+            accumulate (int): The number of steps to accumulate gradident during 
+                training process before optimizer updates. It can mimic large batch
+                size. Default: 1.
             
         Returns:
             None
@@ -2044,7 +2046,8 @@ class Model(object):
 
                 _inputs = [data[:len(self._inputs)], data[len(self._inputs):]]
                 if mode == 'train':
-                    _inputs.append((step + 1) % self._accumulate == 0)
+                    _inputs.append((step + 1) % self._accumulate == 0 or
+                                   step + 1 == len(data_loader))
 
                 outs = getattr(self, mode + '_batch')(*_inputs)
 

python/paddle/tests/test_model.py

@@ -727,12 +727,20 @@ class TestModelFunction(unittest.TestCase):
                                     parameter_list=net.parameters())
         inputs = [InputSpec([None, dim], 'float32', 'x')]
         labels = [InputSpec([None, 1], 'int64', 'label')]
+
         model = Model(net, inputs, labels)
         model.prepare(optim, loss=CrossEntropyLoss(reduction="sum"))
         loss1, = model.train_batch([data], [label], update=False)
         loss2, = model.train_batch([data], [label], update=True)
         np.testing.assert_almost_equal(loss1, loss2, decimal=4)
 
+        model = Model(net, inputs, labels)
+        model.prepare(
+            optim, loss=CrossEntropyLoss(reduction="sum"), amp_configs='O1')
+        loss1, = model.train_batch([data], [label], update=False)
+        loss2, = model.train_batch([data], [label], update=True)
+        np.testing.assert_almost_equal(loss1, loss2, decimal=4)
+
 
 class TestModelWithLRScheduler(unittest.TestCase):
     def test_fit_by_step(self):