【Hackathon 6th No. 27】为 paddle.io.RandomSampler/random_split /Layer.clear_gradients 进行功能增强 -part (#62966)

* update layers sampler and dataset

* update test

* update test

* revise randomsampler num_samples and test

* update error check

* update test

* update docs

* update docs

Author: NKNaN

python/paddle/io/dataloader/dataset.py

@@ -13,6 +13,8 @@
 # limitations under the License.
 
 import bisect
+import math
+import warnings
 from typing import Iterable
 
 import paddle
@@ -487,7 +489,7 @@ def random_split(dataset, lengths, generator=None):
 
     Args:
         dataset (Dataset): Dataset to be split
-        lengths (sequence): lengths of splits to be produced
+        lengths (sequence): lengths or fractions of splits to be produced
         generator (Generator, optional): Generator used for the random permutation. Default is None then the DefaultGenerator is used in manual_seed().
 
     Returns:
@@ -522,6 +524,28 @@ def random_split(dataset, lengths, generator=None):
             5 3
             6 8
     """
+    if math.isclose(sum(lengths), 1) and sum(lengths) <= 1:
+        subset_lengths = []
+        for i, frac in enumerate(lengths):
+            if frac < 0 or frac > 1:
+                raise ValueError(
+                    f"Fraction at index {i} is not between 0 and 1"
+                )
+            n_items_in_split = int(math.floor(len(dataset) * frac))
+            subset_lengths.append(n_items_in_split)
+        remainder = len(dataset) - sum(subset_lengths)
+
+        for i in range(remainder):
+            idx_to_add_at = i % len(subset_lengths)
+            subset_lengths[idx_to_add_at] += 1
+        lengths = subset_lengths
+        for i, length in enumerate(lengths):
+            if length == 0:
+                warnings.warn(
+                    f"Length of split at index {i} is 0. "
+                    f"This might result in an empty dataset."
+                )
+
     # Cannot verify that dataset is Sized
     if sum(lengths) != len(dataset):  # type: ignore
         raise ValueError(

python/paddle/io/dataloader/sampler.py

@@ -160,8 +160,7 @@ class RandomSampler(Sampler):
                 object which implemented :code:`__len__` to get indices as the range of :code:`dataset` length. Default None.
         replacement(bool, optional): If False, sample the whole dataset, If True,
                 set :attr:`num_samples` for how many samples to draw. Default False.
-        num_samples(int, optional): set sample number to draw if :attr:`replacement`
-                is True, then it will take samples according to the number you set. Default None, disabled.
+        num_samples(int, optional): set sample number to draw. Default None, which is set to the length of `data_source`.
         generator(Generator, optional): specify a generator to sample the :code:`data_source`. Default None, disabled.
 
     Returns:
@@ -212,9 +211,10 @@ def __init__(
                 f"replacement={self.replacement}"
             )
 
-        if self._num_samples is not None and not replacement:
+        if not self.replacement and self.num_samples > len(self.data_source):
             raise ValueError(
-                "num_samples should not be specified while replacement is False"
+                "num_samples should be smaller than or equal to length of data_source when replacement is False, "
+                f"but got num_samples: {self.num_samples} > data_source: {len(self.data_source)}"
             )
 
         if not isinstance(self.num_samples, int) or self.num_samples <= 0:
@@ -246,7 +246,7 @@ def __iter__(self):
                     yield index
             else:
                 for index in np.random.choice(
-                    np.arange(n), n, replace=False
+                    np.arange(n), self.num_samples, replace=False
                 ).tolist():
                     yield index
 

python/paddle/nn/layer/layers.py

@@ -1349,10 +1349,14 @@ def named_buffers(self, prefix='', include_sublayers=True):
                 name = layer_prefix + ('.' if layer_prefix else '') + key
                 yield name, buffer
 
-    def clear_gradients(self):
+    def clear_gradients(self, set_to_zero=True):
         """
         Clear the gradients of all parameters for this layer.
 
+        Args:
+            set_to_zero (bool, optional): Whether to set the trainable parameters'
+                gradients to zero or None. Default is True.
+
         Returns:
             None
 
@@ -1375,7 +1379,7 @@ def clear_gradients(self):
         """
         for p in self.parameters():
             if p.trainable:
-                p.clear_gradient()
+                p.clear_gradient(set_to_zero)
 
     def _build_once(self, *args, **kwargs):
         pass

test/legacy_test/test_batch_sampler.py

@@ -87,6 +87,16 @@ def test_with_num_samples(self):
             rets.append(i)
             assert i >= 0 and i < 100
 
+    def test_with_num_samples_and_without_replacement(self):
+        dataset = RandomDataset(100, 10)
+        sampler = RandomSampler(dataset, num_samples=80, replacement=False)
+        assert len(sampler) == 80
+
+        rets = []
+        for i in iter(sampler):
+            rets.append(i)
+            assert i >= 0 and i < 100
+
     def test_with_generator(self):
         dataset = RandomDataset(100, 10)
         generator = iter(range(0, 60))
@@ -111,6 +121,10 @@ def test_with_generator_num_samples(self):
             rets.append(i)
         assert tuple(sorted(rets)) == tuple(range(0, 50))
 
+    def test_with_num_samples_error(self):
+        dataset = RandomDataset(100, 10)
+        self.assertRaises(ValueError, RandomSampler, dataset, False, 120)
+
 
 class TestSubsetRandomSampler(unittest.TestCase):
     def test_main(self):

test/legacy_test/test_dataloader_dataset.py

@@ -89,5 +89,34 @@ def test_multi_process(self):
                     break
 
 
+class TestRandomSplitApi(unittest.TestCase):
+    def test_main(self):
+        paddle.seed(1)
+
+        dataset1, dataset2, dataset3 = paddle.io.random_split(
+            range(5), [0.3, 0.0, 0.7]
+        )
+
+        self.assertTrue(len(dataset1) == 2)
+        self.assertTrue(len(dataset2) == 0)
+        self.assertTrue(len(dataset3) == 3)
+
+        elements_list = list(range(5))
+
+        for _, val in enumerate(dataset1):
+            elements_list.remove(val)
+
+        for _, val in enumerate(dataset3):
+            elements_list.remove(val)
+
+        self.assertTrue(len(elements_list) == 0)
+
+    def test_errors(self):
+        paddle.seed(1)
+        self.assertRaises(
+            ValueError, paddle.io.random_split, range(5), [-0.2, 1.2]
+        )
+
+
 if __name__ == '__main__':
     unittest.main()

test/legacy_test/test_layers.py

@@ -2465,6 +2465,28 @@ def test_support_tuple(self):
             self.assertTrue(model._linear.weight.dtype == paddle.float32)
 
 
+class TestLayerClearGradientSetToZero(unittest.TestCase):
+    def test_layer_clear_gradient_set_to_zero_true(self):
+        with base.dygraph.guard():
+            net = MyLayer()
+            inputs = paddle.randn([10, 1])
+            outputs = net(inputs)
+            outputs.backward()
+            net.clear_gradients()
+            self.assertTrue(
+                net._linear.weight.grad.numpy() == np.array([[0.0]])
+            )
+
+    def test_layer_clear_gradient_set_to_zero_false(self):
+        with base.dygraph.guard():
+            net = MyLayer()
+            inputs = paddle.randn([10, 1])
+            outputs = net(inputs)
+            outputs.backward()
+            net.clear_gradients(set_to_zero=False)
+            self.assertTrue(net._linear.weight.grad is None)
+
+
 if __name__ == '__main__':
     paddle.enable_static()
     unittest.main()