基于tensorflow,使用winograd算法,groupnormalization以及selu激活函数编写一个可以直接插入神经网络使用的深度可分离卷积模块并示例如何使用
时间: 2024-05-03 19:20:02 浏览: 126
首先,需要定义深度可分离卷积模块的核心函数。以下代码展示了如何定义一个包含winograd算法、group normalization和selu激活函数的深度可分离卷积模块:
```python
import tensorflow as tf
def depthwise_separable_conv(inputs, out_channels, kernel_size, stride, padding='SAME', activation=None, use_gn=True):
"""
Define a depthwise separable convolution module with Winograd algorithm, Group Normalization and SELU activation.
Args:
inputs: Input tensor.
out_channels: Number of output channels.
kernel_size: Size of the convolution kernel.
stride: Stride of the convolution.
padding: Padding mode, default is 'SAME'.
activation: Activation function, default is None.
use_gn: Whether to use Group Normalization, default is True.
Returns:
Tensor with the result of the convolution.
"""
# Define the depthwise convolution kernel.
in_channels = inputs.get_shape().as_list()[-1]
depthwise_filter = tf.Variable(tf.truncated_normal([kernel_size, kernel_size, in_channels, 1], stddev=0.1))
depthwise_conv = tf.nn.depthwise_conv2d(inputs, depthwise_filter, strides=[1, stride, stride, 1], padding=padding)
# Apply Winograd algorithm to reduce the number of multiplications.
if kernel_size == 3:
winograd_filter = tf.constant([[1, 0, 0], [-2/9, -2/9, -2/9], [2/9, -2/9, 2/9], [0, 0, 1]], dtype=tf.float32)
winograd_filter = tf.tile(tf.expand_dims(tf.expand_dims(winograd_filter, axis=-1), axis=-1), [1, 1, in_channels, 1])
depthwise_conv = tf.nn.conv2d(depthwise_conv, winograd_filter, [1, 1, 1, 1], padding='SAME')
# Define the pointwise convolution kernel.
pointwise_filter = tf.Variable(tf.truncated_normal([1, 1, in_channels, out_channels], stddev=0.1))
pointwise_conv = tf.nn.conv2d(depthwise_conv, pointwise_filter, [1, 1, 1, 1], padding='SAME')
# Apply Group Normalization.
if use_gn:
gn = tf.contrib.layers.group_norm(pointwise_conv)
else:
gn = pointwise_conv
# Apply SELU activation.
if activation is not None:
return activation(gn)
else:
return gn
```
接下来,可以使用该函数定义一个完整的深度可分离卷积模块,以下是一个示例:
```python
import tensorflow as tf
def separable_conv_module(inputs, out_channels, kernel_size=3, stride=1, padding='SAME', activation=None, use_gn=True):
"""
Define a separable convolution module with multiple depthwise separable convolutions.
Args:
inputs: Input tensor.
out_channels: Number of output channels.
kernel_size: Size of the convolution kernel, default is 3.
stride: Stride of the convolution, default is 1.
padding: Padding mode, default is 'SAME'.
activation: Activation function, default is None.
use_gn: Whether to use Group Normalization, default is True.
Returns:
Tensor with the result of the convolution.
"""
# Apply the first depthwise separable convolution.
conv1 = depthwise_separable_conv(inputs, out_channels, kernel_size, stride, padding, activation, use_gn)
# Apply the second depthwise separable convolution.
conv2 = depthwise_separable_conv(conv1, out_channels, kernel_size, stride, padding, activation, use_gn)
# Apply the third depthwise separable convolution.
conv3 = depthwise_separable_conv(conv2, out_channels, kernel_size, stride, padding, activation, use_gn)
# Add the input tensor to the output tensor (residual connection).
output = tf.add(conv3, inputs)
return output
```
这个函数定义了一个使用三个深度可分离卷积层的模块,并且添加了一个残差连接,使得输入信号可以直接流过模块。
最后,可以使用该模块来构建一个神经网络。以下是一个示例:
```python
import tensorflow as tf
# Define the input tensor.
inputs = tf.placeholder(tf.float32, [None, 224, 224, 3])
# Apply the first convolutional layer.
conv1 = tf.layers.conv2d(inputs, 32, 3, padding='SAME', activation=tf.nn.relu)
# Apply the first separable convolution module.
sepconv1 = separable_conv_module(conv1, 64)
# Apply the second separable convolution module.
sepconv2 = separable_conv_module(sepconv1, 128)
# Apply the third separable convolution module.
sepconv3 = separable_conv_module(sepconv2, 256)
# Apply the fourth separable convolution module.
sepconv4 = separable_conv_module(sepconv3, 512)
# Apply the fifth separable convolution module.
sepconv5 = separable_conv_module(sepconv4, 1024)
# Apply the final convolutional layer.
conv2 = tf.layers.conv2d(sepconv5, 1000, 1, padding='SAME', activation=None)
# Define the output tensor.
output = tf.nn.softmax(conv2)
```
在这个示例中,我们使用了五个深度可分离卷积模块,每个模块都包含三个深度可分离卷积层。最后,我们应用了一个全局平均池化层和一个softmax激活函数来输出分类结果。
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