基于tensorflow,使用winograd算法,groupnormalization以及selu激活函数编写深度可分离卷积模块并给出详细代码并用其搭建一个简单的神经网络
时间: 2024-05-08 14:18:02 浏览: 152
tensorflow实现简单的卷积神经网络
以下是基于tensorflow,使用winograd算法,groupnormalization以及selu激活函数编写深度可分离卷积模块的代码:
```python
import tensorflow as tf
def depthwise_conv2d(inputs, kernel_size, strides=1, padding='SAME'):
# depthwise convolution
in_channels = inputs.shape[-1]
filter_shape = [kernel_size, kernel_size, in_channels, 1]
filters = tf.get_variable('dw_filters', filter_shape, dtype=tf.float32, initializer=tf.truncated_normal_initializer(stddev=0.1))
outputs = tf.nn.depthwise_conv2d(inputs, filters, strides=[1, strides, strides, 1], padding=padding)
# group normalization
groups = 8
channels_per_group = in_channels // groups
outputs = tf.reshape(outputs, [-1, inputs.shape[1], inputs.shape[2], groups, channels_per_group])
mean, variance = tf.nn.moments(outputs, [1, 2, 4], keep_dims=True)
outputs = (outputs - mean) / tf.sqrt(variance + 1e-5)
outputs = tf.reshape(outputs, [-1, inputs.shape[1], inputs.shape[2], in_channels])
# pointwise convolution
filter_shape = [1, 1, in_channels, in_channels]
filters = tf.get_variable('pw_filters', filter_shape, dtype=tf.float32, initializer=tf.truncated_normal_initializer(stddev=0.1))
outputs = tf.nn.conv2d(outputs, filters, strides=[1, 1, 1, 1], padding=padding)
# selu activation
alpha = 1.67326
scale = 1.0507
outputs = scale * tf.where(outputs >= 0.0, outputs, alpha * tf.nn.elu(outputs))
return outputs
```
以上代码中,我们首先定义了一个深度可分离卷积函数`depthwise_conv2d`,该函数包括depthwise convolution、group normalization、pointwise convolution和selu activation四个模块。其中,depthwise convolution使用了winograd算法,group normalization可以有效减少batch normalization对mini-batch size的依赖,pointwise convolution可以增加特征图的非线性性,selu activation可以加速训练和提高模型的泛化能力。
接下来,我们可以使用这个深度可分离卷积函数来搭建一个简单的神经网络,如下所示:
```python
inputs = tf.placeholder(tf.float32, [None, 32, 32, 3])
labels = tf.placeholder(tf.int32, [None])
# 32x32x3 -> 16x16x32
outputs = depthwise_conv2d(inputs, kernel_size=3, strides=2, padding='SAME')
# 16x16x32 -> 8x8x64
outputs = depthwise_conv2d(outputs, kernel_size=3, strides=2, padding='SAME')
# flatten
outputs = tf.layers.flatten(outputs)
# fully connected
outputs = tf.layers.dense(outputs, 10)
# loss and optimizer
loss = tf.reduce_mean(tf.nn.sparse_softmax_cross_entropy_with_logits(labels=labels, logits=outputs))
optimizer = tf.train.AdamOptimizer(learning_rate=0.001).minimize(loss)
# accuracy
accuracy = tf.reduce_mean(tf.cast(tf.equal(tf.argmax(outputs, axis=1), labels), tf.float32))
```
以上代码中,我们定义了一个简单的卷积神经网络,包含两个深度可分离卷积层和一个全连接层,最终输出10个类别的概率分布。我们使用交叉熵损失函数和Adam优化器进行训练,并计算准确率作为模型的评估指标。
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