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Paddle/python/paddle/v2/layers/beam_search.py

133 lines
4.2 KiB

import paddle.v2 as paddle
from paddle.v2.config_base import Layer
from paddle.trainer_config_helpers.default_decorators import wrap_name_default
from paddle.trainer_config_helpers.layers import RecurrentLayerGroupSetGenerator, Generator
class BaseGeneratedInputV2(object):
def __init__(self):
self.bos_id = None
self.eos_id = None
def before_real_step(self):
raise NotImplementedError()
def after_real_step(self, *args):
raise NotImplementedError()
class GeneratedInputV2(BaseGeneratedInputV2):
def __init__(self, size, embedding_name, embedding_size):
super(GeneratedInputV2, self).__init__()
self.size = size
self.embedding_name = embedding_name
self.embedding_size = embedding_size
def after_real_step(self, input):
return paddle.layer.max_id(input=input, name='__beam_search_predict__')
def before_real_step(self):
predict_id = paddle.layer.memory(
name='__beam_search_predict__',
size=self.size,
boot_with_const_id=self.bos_id)
trg_emb = paddle.layer.embedding(
input=predict_id,
size=self.embedding_size,
param_attr=paddle.attr.ParamAttr(name=self.embedding_name))
return trg_emb
class RecurrentLayerGroupSetGeneratorV2(Layer):
def __init__(self, eos_name, max_length, beam_size, num_results_per_sample):
self.eos_name = eos_name
self.max_length = max_length
self.beam_size = beam_size
self.num_results_per_sample = num_results_per_sample
super(RecurrentLayerGroupSetGeneratorV2, self).__init__(
name=eos_name, parent_layers={})
def to_proto_impl(self, context=None, **kwargs):
RecurrentLayerGroupSetGenerator(
Generator(
eos_layer_name=self.eos_name,
max_num_frames=self.max_length,
beam_size=self.beam_size,
num_results_per_sample=self.num_results_per_sample))
return self
def context_name(self):
return self.eos_name + ".fake"
def use_context_name(self):
return True
@wrap_name_default()
def beam_search(step,
input,
bos_id,
eos_id,
beam_size,
max_length=500,
name=None,
num_results_per_sample=None):
if num_results_per_sample is None:
num_results_per_sample = beam_size
assert num_results_per_sample <= beam_size
# logger.warning("num_results_per_sample should be less than beam_size")
if isinstance(input, paddle.layer.StaticInputV2) or isinstance(
input, BaseGeneratedInputV2):
input = [input]
generated_input_index = -1
real_input = []
for i, each_input in enumerate(input):
assert isinstance(each_input, paddle.layer.StaticInputV2) or isinstance(
each_input, BaseGeneratedInputV2)
if isinstance(each_input, BaseGeneratedInputV2):
assert generated_input_index == -1
generated_input_index = i
else:
real_input.append(each_input)
assert generated_input_index != -1
gipt = input[generated_input_index]
assert isinstance(gipt, BaseGeneratedInputV2)
gipt.bos_id = bos_id
gipt.eos_id = eos_id
def __real_step__(*args):
eos_name = "__%s_eos_layer__" % name
generator = RecurrentLayerGroupSetGeneratorV2(
eos_name, max_length, beam_size, num_results_per_sample)
args = list(args)
before_step_layer = gipt.before_real_step()
before_step_layer.append_child(
layer=generator, parent_names=[before_step_layer.name])
args.insert(generated_input_index, before_step_layer)
predict = gipt.after_real_step(step(*args))
eos = paddle.layer.eos(input=predict, eos_id=eos_id, name=eos_name)
predict.append_child(layer=eos, parent_names=[predict.name])
return predict
# tmp = paddle.layer.recurrent_group(
# step=__real_step__,
# input=real_input,
# reverse=False,
# name=name,
# is_generating=True)
tmp = paddle.layer.recurrent_group(
step=__real_step__, input=real_input, name=name)
return tmp