Merge pull request #7770 from peterzhang2029/nmt_fix

enhance the machine_translation model in unittest.

python/paddle/v2/fluid/tests/book/test_machine_translation_encoder_context.py

+#   Copyright (c) 2018 PaddlePaddle Authors. All Rights Reserve.
+#
+# 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 numpy as np
+import paddle.v2 as paddle
+import paddle.v2.fluid as fluid
+import paddle.v2.fluid.core as core
+import paddle.v2.fluid.framework as framework
+import paddle.v2.fluid.layers as layers
+from paddle.v2.fluid.executor import Executor
+
+dict_size = 30000
+source_dict_dim = target_dict_dim = dict_size
+src_dict, trg_dict = paddle.dataset.wmt14.get_dict(dict_size)
+hidden_dim = 32
+embedding_dim = 16
+batch_size = 10
+max_length = 50
+topk_size = 50
+encoder_size = decoder_size = hidden_dim
+IS_SPARSE = True
+USE_PEEPHOLES = False
+
+
+def bi_lstm_encoder(input_seq, hidden_size):
+    input_forward_proj = fluid.layers.fc(input=input_seq,
+                                         size=hidden_size * 4,
+                                         bias_attr=True)
+    forward, _ = fluid.layers.dynamic_lstm(
+        input=input_forward_proj,
+        size=hidden_size * 4,
+        use_peepholes=USE_PEEPHOLES)
+    input_backward_proj = fluid.layers.fc(input=input_seq,
+                                          size=hidden_size * 4,
+                                          bias_attr=True)
+    backward, _ = fluid.layers.dynamic_lstm(
+        input=input_backward_proj,
+        size=hidden_size * 4,
+        is_reverse=True,
+        use_peepholes=USE_PEEPHOLES)
+    return forward, backward
+
+
+# FIXME(peterzhang2029): Replace this function with the lstm_unit_op.
+def lstm_step(x_t, hidden_t_prev, cell_t_prev, size):
+    def linear(inputs):
+        return fluid.layers.fc(input=inputs, size=size, bias_attr=True)
+
+    forget_gate = fluid.layers.sigmoid(x=linear([hidden_t_prev, x_t]))
+    input_gate = fluid.layers.sigmoid(x=linear([hidden_t_prev, x_t]))
+    output_gate = fluid.layers.sigmoid(x=linear([hidden_t_prev, x_t]))
+    cell_tilde = fluid.layers.tanh(x=linear([hidden_t_prev, x_t]))
+
+    cell_t = fluid.layers.sums(input=[
+        fluid.layers.elementwise_mul(
+            x=forget_gate, y=cell_t_prev), fluid.layers.elementwise_mul(
+                x=input_gate, y=cell_tilde)
+    ])
+
+    hidden_t = fluid.layers.elementwise_mul(
+        x=output_gate, y=fluid.layers.tanh(x=cell_t))
+
+    return hidden_t, cell_t
+
+
+def lstm_decoder_without_attention(target_embedding, decoder_boot, context,
+                                   decoder_size):
+    rnn = fluid.layers.DynamicRNN()
+
+    cell_init = fluid.layers.fill_constant_batch_size_like(
+        input=decoder_boot,
+        value=0.0,
+        shape=[-1, decoder_size],
+        dtype='float32')
+    cell_init.stop_gradient = False
+
+    with rnn.block():
+        current_word = rnn.step_input(target_embedding)
+        context = rnn.static_input(context)
+
+        hidden_mem = rnn.memory(init=decoder_boot, need_reorder=True)
+        cell_mem = rnn.memory(init=cell_init)
+        decoder_inputs = fluid.layers.concat(
+            input=[context, current_word], axis=1)
+        h, c = lstm_step(decoder_inputs, hidden_mem, cell_mem, decoder_size)
+        rnn.update_memory(hidden_mem, h)
+        rnn.update_memory(cell_mem, c)
+        out = fluid.layers.fc(input=h,
+                              size=target_dict_dim,
+                              bias_attr=True,
+                              act='softmax')
+        rnn.output(out)
+    return rnn()
+
+
+def seq_to_seq_net():
+    """Construct a seq2seq network."""
+
+    src_word_idx = fluid.layers.data(
+        name='source_sequence', shape=[1], dtype='int64', lod_level=1)
+
+    src_embedding = fluid.layers.embedding(
+        input=src_word_idx,
+        size=[source_dict_dim, embedding_dim],
+        dtype='float32')
+
+    src_forward, src_backward = bi_lstm_encoder(
+        input_seq=src_embedding, hidden_size=encoder_size)
+
+    encoded_vector = fluid.layers.concat(
+        input=[src_forward, src_backward], axis=1)
+
+    enc_vec_last = fluid.layers.sequence_last_step(input=encoded_vector)
+
+    decoder_boot = fluid.layers.fc(input=enc_vec_last,
+                                   size=decoder_size,
+                                   bias_attr=False,
+                                   act='tanh')
+
+    trg_word_idx = fluid.layers.data(
+        name='target_sequence', shape=[1], dtype='int64', lod_level=1)
+
+    trg_embedding = fluid.layers.embedding(
+        input=trg_word_idx,
+        size=[target_dict_dim, embedding_dim],
+        dtype='float32')
+
+    prediction = lstm_decoder_without_attention(trg_embedding, decoder_boot,
+                                                enc_vec_last, decoder_size)
+    label = fluid.layers.data(
+        name='label_sequence', shape=[1], dtype='int64', lod_level=1)
+    cost = fluid.layers.cross_entropy(input=prediction, label=label)
+    avg_cost = fluid.layers.mean(x=cost)
+
+    return avg_cost
+
+
+def to_lodtensor(data, place):
+    seq_lens = [len(seq) for seq in data]
+    cur_len = 0
+    lod = [cur_len]
+    for l in seq_lens:
+        cur_len += l
+        lod.append(cur_len)
+    flattened_data = np.concatenate(data, axis=0).astype("int64")
+    flattened_data = flattened_data.reshape([len(flattened_data), 1])
+    res = core.LoDTensor()
+    res.set(flattened_data, place)
+    res.set_lod([lod])
+    return res
+
+
+def main():
+    avg_cost = seq_to_seq_net()
+
+    optimizer = fluid.optimizer.Adagrad(learning_rate=1e-4)
+    optimizer.minimize(avg_cost)
+
+    train_data = paddle.batch(
+        paddle.reader.shuffle(
+            paddle.dataset.wmt14.train(dict_size), buf_size=1000),
+        batch_size=batch_size)
+
+    place = core.CPUPlace()
+    exe = Executor(place)
+
+    exe.run(framework.default_startup_program())
+
+    batch_id = 0
+    for pass_id in xrange(2):
+        for data in train_data():
+            word_data = to_lodtensor(map(lambda x: x[0], data), place)
+            trg_word = to_lodtensor(map(lambda x: x[1], data), place)
+            trg_word_next = to_lodtensor(map(lambda x: x[2], data), place)
+            outs = exe.run(framework.default_main_program(),
+                           feed={
+                               'source_sequence': word_data,
+                               'target_sequence': trg_word,
+                               'label_sequence': trg_word_next
+                           },
+                           fetch_list=[avg_cost])
+            avg_cost_val = np.array(outs[0])
+            print('pass_id=' + str(pass_id) + ' batch=' + str(batch_id) +
+                  " avg_cost=" + str(avg_cost_val))
+            if batch_id > 3:
+                exit(0)
+            batch_id += 1
+
+
+if __name__ == '__main__':
+    main()