desc.py

# Copyright (c) 2019 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.

# The placeholder for batch_size in compile time. Must be -1 currently to be
# consistent with some ops' infer-shape output in compile time, such as the
# sequence_expand op used in beamsearch decoder.
batch_size = None
# The placeholder for squence length in compile time.
seq_len = None
# The placeholder for head number in compile time.
n_head = 8
# The placeholder for model dim in compile time.
d_model = 512
# Here list the data shapes and data types of all inputs.
# The shapes here act as placeholder and are set to pass the infer-shape in
# compile time.
input_descs = {
    # The actual data shape of src_word is:
    # [batch_size, max_src_len_in_batch]
    "src_word": [(batch_size, seq_len), "int64", 2],
    # The actual data shape of src_pos is:
    # [batch_size, max_src_len_in_batch, 1]
    "src_pos": [(batch_size, seq_len), "int64"],
    # This input is used to remove attention weights on paddings in the
    # encoder.
    # The actual data shape of src_slf_attn_bias is:
    # [batch_size, n_head, max_src_len_in_batch, max_src_len_in_batch]
    "src_slf_attn_bias": [(batch_size, n_head, seq_len, seq_len), "float32"],
    # The actual data shape of trg_word is:
    # [batch_size, max_trg_len_in_batch, 1]
    "trg_word": [(batch_size, seq_len), "int64",
                 2],  # lod_level is only used in fast decoder.
    # The actual data shape of trg_pos is:
    # [batch_size, max_trg_len_in_batch, 1]
    "trg_pos": [(batch_size, seq_len), "int64"],
    # This input is used to remove attention weights on paddings and
    # subsequent words in the decoder.
    # The actual data shape of trg_slf_attn_bias is:
    # [batch_size, n_head, max_trg_len_in_batch, max_trg_len_in_batch]
    "trg_slf_attn_bias": [(batch_size, n_head, seq_len, seq_len), "float32"],
    # This input is used to remove attention weights on paddings of the source
    # input in the encoder-decoder attention.
    # The actual data shape of trg_src_attn_bias is:
    # [batch_size, n_head, max_trg_len_in_batch, max_src_len_in_batch]
    "trg_src_attn_bias": [(batch_size, n_head, seq_len, seq_len), "float32"],
    # This input is used in independent decoder program for inference.
    # The actual data shape of enc_output is:
    # [batch_size, max_src_len_in_batch, d_model]
    "enc_output": [(batch_size, seq_len, d_model), "float32"],
    # The actual data shape of label_word is:
    # [batch_size * max_trg_len_in_batch, 1]
    "lbl_word": [(None, 1), "int64"],
    # This input is used to mask out the loss of paddding tokens.
    # The actual data shape of label_weight is:
    # [batch_size * max_trg_len_in_batch, 1]
    "lbl_weight": [(None, 1), "float32"],
    # This input is used in beam-search decoder.
    "init_score": [(batch_size, 1), "float32", 2],
    # This input is used in beam-search decoder for the first gather
    # (cell states updation)
    "init_idx": [(batch_size, ), "int32"],
}

# Names of word embedding table which might be reused for weight sharing.
word_emb_param_names = (
    "src_word_emb_table",
    "trg_word_emb_table", )
# Names of position encoding table which will be initialized externally.
pos_enc_param_names = (
    "src_pos_enc_table",
    "trg_pos_enc_table", )
# separated inputs for different usages.
encoder_data_input_fields = (
    "src_word",
    "src_pos",
    "src_slf_attn_bias", )
decoder_data_input_fields = (
    "trg_word",
    "trg_pos",
    "trg_slf_attn_bias",
    "trg_src_attn_bias",
    "enc_output", )
label_data_input_fields = (
    "lbl_word",
    "lbl_weight", )
# In fast decoder, trg_pos (only containing the current time step) is generated
# by ops and trg_slf_attn_bias is not needed.
fast_decoder_data_input_fields = (
    "trg_word",
    "init_score",
    "init_idx",
    "trg_src_attn_bias", )