# coding=utf-8
# Copyright 2021 The OneFlow 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 enum import Enum
from typing import Optional
import oneflow as flow
from oneflow import nn
class Activation(str, Enum):
SquaredReLU = "squared_relu"
GeLU = "gelu"
GeLUTanh = "gelu_tanh"
LeakyReLU = "leaky_relu"
ReLU = "relu"
Tanh = "tanh"
QuickGELU = "quick_gelu"
# For unit testing / parity comparisons, probably not the fastest way
class SquaredReLU(nn.Module):
def __init__(self) -> None:
super().__init__()
def forward(self, x: flow.Tensor) -> flow.Tensor:
x_ = flow._C.relu(x)
return x_ * x_
class Passthrough(nn.Module):
def __init__(self) -> None:
super().__init__()
def forward(self, x: flow.Tensor) -> flow.Tensor:
return x
class GeLUTanh(nn.Module):
def __init__(self) -> None:
super().__init__()
def forward(self, x: flow.Tensor) -> flow.Tensor:
"""When the approximate argument is 'tanh', Gelu is estimated with:
0.5 * x * (1.0 + flow.tanh(math.sqrt(2.0 / math.pi) * (x + 0.044715 * flow.pow(x, 3.0))))
"""
return flow.nn.functional.gelu(x, approximate="tanh")
class QuickGELU(nn.Module):
def __init__(self) -> None:
super().__init__()
def forward(self, x: flow.Tensor) -> flow.Tensor:
"""QuickGELU is estimated with: x * flow.sigmoid(1.702 * x)"""
return flow._C.quick_gelu(x)
[docs]def build_activation(activation: Optional[Activation]):
"""
Fetching activation layers by name, e.g.,
``build_activation("gelu")`` returns ``nn.GELU()`` module.
"""
if not activation:
return Passthrough()
return {
Activation.ReLU: nn.ReLU,
Activation.GeLU: nn.GELU,
Activation.GeLUTanh: GeLUTanh,
Activation.LeakyReLU: nn.LeakyReLU,
Activation.SquaredReLU: SquaredReLU,
Activation.Tanh: nn.Tanh,
Activation.QuickGELU: QuickGELU,
}[activation]()