code: # Copyright (c) 2018 PaddlePaddle Authors. All Rights Reserved.
  #
  # Licensed under the Apache License, Version 2.0 (the "License");
  # you may not use this file except in compliance with the License.
  # You may obtain a copy of the License at
  #
  #     http://www.apache.org/licenses/LICENSE-2.0
  #
  # Unless required by applicable law or agreed to in writing, software
  # distributed under the License is distributed on an "AS IS" BASIS,
  # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  # See the License for the specific language governing permissions and
  # limitations under the License.
  
  import unittest
  import numpy as np
  import random
  import os
  import sys
  
  import paddle
  import paddle.fluid as fluid
  import paddle.fluid.core as core
  from test_imperative_base import new_program_scope
  from paddle.fluid.dygraph.base import to_variable
  from paddle.fluid.dygraph import Linear
  
  # Can use Amusic dataset as the DeepCF describes.
  DATA_PATH = os.environ.get('DATA_PATH', '')
  
  BATCH_SIZE = int(os.environ.get('BATCH_SIZE', 128))
  NUM_BATCHES = int(os.environ.get('NUM_BATCHES', 5))
  NUM_EPOCHES = int(os.environ.get('NUM_EPOCHES', 1))
  
  
  class DMF(fluid.Layer):
      def __init__(self):
          super(DMF, self).__init__()
          self._user_latent = Linear(1000, 256)
          self._item_latent = Linear(100, 256)
  
          self._user_layers = []
          self._item_layers = []
          self._hid_sizes = [128, 64]
          for i in range(len(self._hid_sizes)):
              self._user_layers.append(
                  self.add_sublayer(
                      'user_layer_%d' % i,
                      Linear(
                          256 if i == 0 else self._hid_sizes[i - 1],
                          self._hid_sizes[i],
                          act='relu')))
              self._item_layers.append(
                  self.add_sublayer(
                      'item_layer_%d' % i,
                      Linear(
                          256 if i == 0 else self._hid_sizes[i - 1],
                          self._hid_sizes[i],
                          act='relu')))
  
      def forward(self, users, items):
          users = self._user_latent(users)
          items = self._item_latent(items)
  
          for ul, il in zip(self._user_layers, self._item_layers):
              users = ul(users)
              items = il(items)
          return fluid.layers.elementwise_mul(users, items)
  
  
  class MLP(fluid.Layer):
      def __init__(self):
          super(MLP, self).__init__()
          self._user_latent = Linear(1000, 256)
          self._item_latent = Linear(100, 256)
          self._match_layers = []
          self._hid_sizes = [128, 64]
          for i in range(len(self._hid_sizes)):
              self._match_layers.append(
                  self.add_sublayer(
                      'match_layer_%d' % i,
                      Linear(
                          256 * 2 if i == 0 else self._hid_sizes[i - 1],
                          self._hid_sizes[i],
                          act='relu')))
  
      def forward(self, users, items):
          users = self._user_latent(users)
          items = self._item_latent(items)
          match_vec = fluid.layers.concat(
              [users, items], axis=len(users.shape) - 1)
          for l in self._match_layers:
              match_vec = l(match_vec)
          return match_vec
  
  
  class DeepCF(fluid.Layer):
      def __init__(self, num_users, num_items, matrix):
          super(DeepCF, self).__init__()
          self._num_users = num_users
          self._num_items = num_items
          self._rating_matrix = self.create_parameter(
              attr=fluid.ParamAttr(trainable=False),
              shape=matrix.shape,
              dtype=matrix.dtype,
              is_bias=False,
              default_initializer=fluid.initializer.NumpyArrayInitializer(matrix))
          self._rating_matrix.stop_gradient = True
  
          self._mlp = MLP()
          self._dmf = DMF()
          self._match_fc = Linear(128, 1, act='sigmoid')
  
      def forward(self, users, items):
          # users_emb = self._user_emb(users)
          # items_emb = self._item_emb(items)
          users_emb = fluid.layers.gather(self._rating_matrix, users)
          items_emb = fluid.layers.gather(
              fluid.layers.transpose(self._rating_matrix, [1, 0]), items)
          users_emb.stop_gradient = True
          items_emb.stop_gradient = True
  
          mlp_predictive = self._mlp(users_emb, items_emb)
          dmf_predictive = self._dmf(users_emb, items_emb)
          predictive = fluid.layers.concat(
              [mlp_predictive, dmf_predictive],
              axis=len(mlp_predictive.shape) - 1)
          prediction = self._match_fc(predictive)
          return prediction
  
  
  def get_data():
      user_ids = []
      item_ids = []
      labels = []
      NUM_USERS = 100
      NUM_ITEMS = 1000
      matrix = np.zeros([NUM_USERS, NUM_ITEMS], dtype=np.float32)
  
      for uid in range(NUM_USERS):
          for iid in range(NUM_ITEMS):
              label = float(random.randint(1, 6) == 1)
              user_ids.append(uid)
              item_ids.append(iid)
              labels.append(label)
              matrix[uid, iid] = label
      indices = np.arange(len(user_ids))
      np.random.shuffle(indices)
      users_np = np.array(user_ids, dtype=np.int32)[indices]
      items_np = np.array(item_ids, dtype=np.int32)[indices]
      labels_np = np.array(labels, dtype=np.float32)[indices]
      return np.expand_dims(users_np, -1), \
             np.expand_dims(items_np, -1), \
             np.expand_dims(labels_np, -1), NUM_USERS, NUM_ITEMS, matrix
  
  
  def load_data(DATA_PATH):
      sys.stderr.write('loading from %s\n' % DATA_PATH)
      likes = dict()
      num_users = -1
      num_items = -1
      with open(DATA_PATH, 'r') as f:
          for l in f.readlines():
              uid, iid, rating = [int(v) for v in l.split('\t')]
              num_users = max(num_users, uid + 1)
              num_items = max(num_items, iid + 1)
              if float(rating) > 0.0:
                  likes[(uid, iid)] = 1.0
  
      user_ids = []
      item_ids = []
      labels = []
      matrix = np.zeros([num_users, num_items], dtype=np.float32)
      for uid, iid in likes.keys():
          user_ids.append(uid)
          item_ids.append(iid)
          labels.append(1.0)
          matrix[uid, iid] = 1.0
  
          negative = 0
          while negative < 3:
              nuid = random.randint(0, num_users - 1)
              niid = random.randint(0, num_items - 1)
              if (nuid, niid) not in likes:
                  negative += 1
                  user_ids.append(nuid)
                  item_ids.append(niid)
                  labels.append(0.0)
  
      indices = np.arange(len(user_ids))
      np.random.shuffle(indices)
      users_np = np.array(user_ids, dtype=np.int32)[indices]
      items_np = np.array(item_ids, dtype=np.int32)[indices]
      labels_np = np.array(labels, dtype=np.float32)[indices]
      return np.expand_dims(users_np, -1), \
             np.expand_dims(items_np, -1), \
             np.expand_dims(labels_np, -1), num_users, num_items, matrix
  
  
  class TestDygraphDeepCF(unittest.TestCase):
      def test_deefcf(self):
          seed = 90
          if DATA_PATH:
              (users_np, items_np, labels_np, num_users, num_items,
               matrix) = load_data(DATA_PATH)
          else:
              (users_np, items_np, labels_np, num_users, num_items,
               matrix) = get_data()
  
          startup = fluid.Program()
          startup.random_seed = seed
          main = fluid.Program()
          main.random_seed = seed
  
          scope = fluid.core.Scope()
          with new_program_scope(main=main, startup=startup, scope=scope):
              users = fluid.layers.data('users', [1], dtype='int32')
              items = fluid.layers.data('items', [1], dtype='int32')
              labels = fluid.layers.data('labels', [1], dtype='float32')
  
              deepcf = DeepCF(num_users, num_items, matrix)
              prediction = deepcf(users, items)
              loss = fluid.layers.reduce_sum(
                  fluid.layers.log_loss(prediction, labels))
              adam = fluid.optimizer.AdamOptimizer(0.01)
              adam.minimize(loss)
  
              exe = fluid.Executor(fluid.CPUPlace(
              ) if not core.is_compiled_with_cuda() else fluid.CUDAPlace(0))
              exe.run(startup)
              for e in range(NUM_EPOCHES):
                  sys.stderr.write('epoch %d\n' % e)
                  for slice in range(0, BATCH_SIZE * NUM_BATCHES, BATCH_SIZE):
                      if slice + BATCH_SIZE >= users_np.shape[0]:
                          break
                      static_loss = exe.run(
                          main,
                          feed={
                              users.name: users_np[slice:slice + BATCH_SIZE],
                              items.name: items_np[slice:slice + BATCH_SIZE],
                              labels.name: labels_np[slice:slice + BATCH_SIZE]
                          },
                          fetch_list=[loss])[0]
                      sys.stderr.write('static loss %s\n' % static_loss)
  
          with fluid.dygraph.guard():
              fluid.default_startup_program().random_seed = seed
              fluid.default_main_program().random_seed = seed
  
              deepcf = DeepCF(num_users, num_items, matrix)
              adam = fluid.optimizer.AdamOptimizer(
                  0.01, parameter_list=deepcf.parameters())
              for e in range(NUM_EPOCHES):
                  sys.stderr.write('epoch %d\n' % e)
                  for slice in range(0, BATCH_SIZE * NUM_BATCHES, BATCH_SIZE):
                      if slice + BATCH_SIZE >= users_np.shape[0]:
                          break
                      prediction = deepcf(
                          to_variable(users_np[slice:slice + BATCH_SIZE]),
                          to_variable(items_np[slice:slice + BATCH_SIZE]))
                      loss = fluid.layers.reduce_sum(
                          fluid.layers.log_loss(prediction,
                                                to_variable(labels_np[
                                                    slice:slice + BATCH_SIZE])))
                      loss.backward()
                      adam.minimize(loss)
                      deepcf.clear_gradients()
                      dy_loss = loss.numpy()
                      sys.stderr.write('dynamic loss: %s %s\n' % (slice, dy_loss))
  
          with fluid.dygraph.guard():
              fluid.default_startup_program().random_seed = seed
              fluid.default_main_program().random_seed = seed
  
              deepcf2 = DeepCF(num_users, num_items, matrix)
              adam2 = fluid.optimizer.AdamOptimizer(
                  0.01, parameter_list=deepcf2.parameters())
              backward_strategy = fluid.dygraph.BackwardStrategy()
              backward_strategy.sort_sum_gradient = True
              for e in range(NUM_EPOCHES):
                  sys.stderr.write('epoch %d\n' % e)
                  for slice in range(0, BATCH_SIZE * NUM_BATCHES, BATCH_SIZE):
                      if slice + BATCH_SIZE >= users_np.shape[0]:
                          break
                      prediction2 = deepcf2(
                          to_variable(users_np[slice:slice + BATCH_SIZE]),
                          to_variable(items_np[slice:slice + BATCH_SIZE]))
                      loss2 = fluid.layers.reduce_sum(
                          fluid.layers.log_loss(prediction2,
                                                to_variable(labels_np[
                                                    slice:slice + BATCH_SIZE])))
                      loss2.backward(backward_strategy)
                      adam2.minimize(loss2)
                      deepcf2.clear_gradients()
                      dy_loss2 = loss2.numpy()
                      sys.stderr.write('dynamic loss: %s %s\n' %
                                       (slice, dy_loss2))
  
          self.assertEqual(static_loss, dy_loss)
          self.assertEqual(static_loss, dy_loss2)
  
  
  if __name__ == '__main__':
      unittest.main()
  
apis: numpy.array numpy.random.shuffle numpy.expand_dims numpy.zeros