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Paddle/python/paddle/nn/functional/input.py

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# Copyright (c) 2020 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.
from __future__ import print_function
import warnings
from ...fluid.framework import Variable, in_dygraph_mode
from ...fluid.layer_helper import LayerHelper
from ...fluid.layers import core
from ...fluid.data_feeder import check_variable_and_dtype, check_dtype
__all__ = ['one_hot', 'embedding']
def one_hot(x, num_classes, name=None):
"""
The operator converts each id in the input 'x' to an one-hot vector with a
num_classes length. The value in the vector dimension corresponding to the id
is 1, and the value in the remaining dimension is 0.
The shape of output Tensor is generated by appending num_classes dimension
behind the last dimension of the 'x' shape.
.. code-block:: text
Example 1:
input:
x.shape = [4]
x.data = [1, 1, 3, 0]
num_classes = 4
output:
Out.shape = [4, 4]
Out.data = [[0., 1., 0., 0.],
[0., 1., 0., 0.],
[0., 0., 0., 1.],
[1., 0., 0., 0.]]
Example 2:
input:
x.shape = [4]
x.data = [1, 1, 5, 0]
num_classes = 4
output: Throw an exception for Illegal value
The second dimension in X is 5, which is greater than num_classes,
so it throws an exception.
Args:
x(Tensor): Tensor with shape :math:`[N_1, N_2, ..., N_k]` ,
which contains at least one dimension. The data type is int32 or int64.
num_classes(int): An integer defining the num_classes of the one hot dimension. If input 'x'
is word id, num_classes is generally the dictionary size.
Returns:
Tensor: The one-hot representations of 'x'. A Tensor with type float32.
Examples:
.. code-block:: python
import paddle
# Correspond to the first example above, where label.shape is 4 and one_hot_label.shape is [4, 4].
label = paddle.fluid.data(name="label", shape=[4, 1], dtype="int64")
# label.shape = [4]
# label.data = [1, 1, 3, 0]
one_hot_label = paddle.nn.functional.one_hot(x=label, num_classes=4)
# one_hot_label.shape = [4, 4]
# one_hot_label.data = [[0., 1., 0., 0.],
# [0., 1., 0., 0.],
# [0., 0., 0., 1.],
# [1., 0., 0., 0.]]
"""
if in_dygraph_mode():
return core.ops.one_hot_v2(x, 'depth', num_classes,
'allow_out_of_range', False)
else:
check_variable_and_dtype(x, 'input', ['int32', 'int64'], 'one_hot_v2')
helper = LayerHelper("one_hot_v2", **locals())
one_hot_out = helper.create_variable_for_type_inference(dtype='float32')
if not isinstance(num_classes, Variable):
# user attribute
inputs = {'X': x}
attrs = {'depth': num_classes, 'allow_out_of_range': False}
else:
num_classes.stop_gradient = True
inputs = {'X': x, 'depth_tensor': num_classes}
attrs = {'allow_out_of_range': False}
helper.append_op(
type="one_hot_v2",
inputs=inputs,
attrs=attrs,
outputs={'Out': one_hot_out},
stop_gradient=True)
return one_hot_out
def embedding(x, weight, padding_idx=None, sparse=False, name=None):
"""
The operator is used to lookup embeddings vector of ids provided by :attr:`x` .
The shape of output Tensor is generated by appending the last dimension of the input Tensor shape
with embedding size.
**Note:** The id in :attr:`x` must satisfy :math:`0 =< id < weight.shape[0]` ,
otherwise the program will throw an exception and exit.
.. code-block:: text
Case 1:
x is a Tensor.
padding_idx = -1
x.data = [[1, 3], [2, 4], [4, 127]]
x.shape = [3, 2]
weight.shape = [128, 16]
output is a Tensor:
out.shape = [3, 2, 16]
out.data = [[[0.129435295, 0.244512452, ..., 0.436322452],
[0.345421456, 0.524563927, ..., 0.144534654]],
[[0.345249859, 0.124939536, ..., 0.194353745],
[0.945345345, 0.435394634, ..., 0.435345365]],
[[0.945345345, 0.435394634, ..., 0.435345365],
[0.0, 0.0, ..., 0.0 ]]] # padding data
The input padding_idx is less than 0, it is automatically converted to padding_idx = -1 + 128 = 127
It will pad all-zero data when id is 127.
Args:
x(Tensor): A Tensor with type int32/int64, which contains the id information. The value of the input id should
satisfy :math:`0<= id < weight.shape[0]` .
weight (Tensor): The weight. A Tensor with shape of lookup table parameter. It should have two elements which
indicates the size of the dictionary of embeddings and the size of each embedding vector respectively.
sparse(bool): The flag indicating whether to use sparse update. This parameter only
affects the performance of the backwards gradient update. It is recommended to set
True because sparse update is faster. But some optimizers does not support sparse update,
such as :ref:`api_optimizer_AdadeltaOptimizer` , :ref:`api_optimizer_AdamaxOptimizer` ,
:ref:`api_optimizer_DecayedAdagradOptimizer` , :ref:`api_optimizer_FtrlOptimizer` ,
:ref:`api_optimizer_LambOptimizer` and :ref:`api_optimizer_LarsMomentumOptimizer` .
In these cases, sparse must be False. Default: False.
padding_idx(int|long|None): padding_idx needs to be in the interval [-weight.shape[0], weight.shape[0]).
If :math:`padding\_idx < 0`, the :math:`padding\_idx` will automatically be converted
to :math:`weight.shape[0] + padding\_idx` . It will output all-zero padding data whenever lookup
encounters :math:`padding\_idx` in id. And the padding data will not be updated while training.
If set None, it makes no effect to output. Default: None.
name(str|None): For detailed information, please refer
to :ref:`api_guide_Name`. Usually name is no need to set and
None by default.
Returns:
Tensor: Embedding Tensor mapped by x. The data type is the same as :attr:`weight`.
Examples:
.. code-block:: python
import paddle
import paddle.nn as nn
weight = prog.global_block().create_parameter(
attr=self._param_attr,
shape=param_shape,
dtype=self._dtype,
default_initializer=Constant(1.0))
prog = paddle.static.Program()
weight = prog.global_block().create_parameter(
(128, 100), dtype="float32", default_initializer=Constant(1.0))
label = paddle.fluid.data(
name="label",
shape=[4],
append_batch_size=False,
dtype="int64")
emb = nn.embedding(
x=label, weight=weight, sparse=True, name="embedding")
"""
if in_dygraph_mode():
return core.ops.lookup_table_v2(
weight, x, 'is_sparse', sparse, 'is_distributed', False,
'remote_prefetch', False, 'padding_idx', padding_idx)
else:
helper = LayerHelper('embedding', **locals())
dtype = helper.input_dtype()
check_variable_and_dtype(x, 'input', ['int32', 'int64'], 'embedding')
is_distributed = False
remote_prefetch = sparse and (not is_distributed)
tmp = helper.create_variable_for_type_inference(dtype)
padding_idx = -1 if padding_idx is None else padding_idx if padding_idx >= 0 else (
weight.shape[0] + padding_idx)
if padding_idx >= weight.shape[0] or padding_idx < -weight.shape[0]:
raise ValueError("padding_idx must be within [-{}, {})".format(
weight.shape[0], weight.shape[0]))
helper.append_op(
type='lookup_table_v2',
inputs={'Ids': x,
'W': weight},
outputs={'Out': tmp},
attrs={
'is_sparse': sparse,
'is_distributed': is_distributed,
'remote_prefetch': remote_prefetch,
'padding_idx': padding_idx
})
return tmp