# Copyright 2021 Huawei Technologies Co., Ltd
#
# 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.
# ============================================================================
"""less Batch Normalization"""
import numpy as np
from mindspore.nn.cell import Cell
from mindspore.nn.layer import Dense
from mindspore.ops import operations as P
from mindspore.common import Tensor, Parameter
from mindspore.common import dtype as mstype
from mindspore.common.initializer import initializer
__all__ = ["CommonHeadLastFN", "LessBN"]
class CommonHeadLastFN(Cell):
r"""
The last full Normalization layer.
This layer implements the operation as:
.. math::
\text{inputs} = \text{norm}(\text{inputs})
\text{kernel} = \text{norm}(\text{kernel})
\text{outputs} = \text{multiplier} * (\text{inputs} * \text{kernel} + \text{bias}),
Args:
in_channels (int): The number of channels in the input space.
out_channels (int): The number of channels in the output space.
weight_init (Union[Tensor, str, Initializer, numbers.Number]): The trainable weight_init parameter. The dtype
is same as input x. The values of str refer to the function `initializer`. Default: 'normal'.
bias_init (Union[Tensor, str, Initializer, numbers.Number]): The trainable bias_init parameter. The dtype is
same as input x. The values of str refer to the function `initializer`. Default: 'zeros'.
has_bias (bool): Specifies whether the layer uses a bias vector. Default: True.
Supported Platforms:
``Ascend`` ``GPU`` ``CPU``
Examples:
>>> input = Tensor(np.array([[180, 234, 154], [244, 48, 247]]), mindspore.float32)
>>> net = CommonHeadLastFN(3, 4)
>>> output = net(input)
"""
def __init__(self,
in_channels,
out_channels,
weight_init='normal',
bias_init='zeros',
has_bias=True):
super(CommonHeadLastFN, self).__init__()
weight_shape = [out_channels, in_channels]
self.weight = Parameter(initializer(weight_init, weight_shape), requires_grad=True, name='weight')
self.x_norm = P.L2Normalize(axis=1)
self.w_norm = P.L2Normalize(axis=1)
self.fc = P.MatMul(transpose_a=False, transpose_b=True)
self.multiplier = Parameter(Tensor(np.ones([1]), mstype.float32), requires_grad=True, name='multiplier')
self.has_bias = has_bias
if self.has_bias:
bias_shape = [out_channels]
self.bias_add = P.BiasAdd()
self.bias = Parameter(initializer(bias_init, bias_shape), requires_grad=True, name='bias')
def construct(self, x):
x = self.x_norm(x)
w = self.w_norm(self.weight)
x = self.fc(x, w)
if self.has_bias:
x = self.bias_add(x, self.bias)
x = self.multiplier * x
return x
[docs]class LessBN(Cell):
"""
Reduce the number of BN automatically to improve the network performance
and ensure the network accuracy.
Args:
network (Cell): Network to be modified.
fn_flag (bool): Replace FC with FN. default: False.
Examples:
>>> network = boost.LessBN(network)
"""
def __init__(self, network, fn_flag=False):
super(LessBN, self).__init__()
self.network = network
self.network.set_boost("less_bn")
self.network.update_cell_prefix()
if fn_flag:
self._convert_to_less_bn_net(self.network)
self.network.add_flags(defer_inline=True)
def _convert_dense(self, subcell):
"""
convert dense cell to FN cell
"""
prefix = subcell.param_prefix
new_subcell = CommonHeadLastFN(subcell.in_channels,
subcell.out_channels,
subcell.weight,
subcell.bias,
False)
new_subcell.update_parameters_name(prefix + '.')
return new_subcell
def _convert_to_less_bn_net(self, net):
"""
convert network to less_bn network
"""
cells = net.name_cells()
dense_name = []
dense_list = []
for name in cells:
subcell = cells[name]
if subcell == net:
continue
elif isinstance(subcell, (Dense)):
dense_name.append(name)
dense_list.append(subcell)
else:
self._convert_to_less_bn_net(subcell)
if dense_list:
new_subcell = self._convert_dense(dense_list[-1])
net.insert_child_to_cell(dense_name[-1], new_subcell)
def construct(self, *inputs):
return self.network(*inputs)