下面是关于“Pytorch转keras的有效方法,以FlowNet为例讲解”的完整攻略。
Pytorch转keras的有效方法
在将Pytorch模型转换为Keras模型时,我们可以使用以下方法。
方法1:手动转换
我们可以手动将Pytorch模型转换为Keras模型。这需要我们了解Pytorch和Keras的模型结构和参数。我们可以使用以下代码来手动转换模型。
import torch
import torch.nn as nn
from keras.models import Sequential
from keras.layers import Conv2D, BatchNormalization, Activation, MaxPooling2D, Flatten, Dense
# 定义Pytorch模型
class FlowNet(nn.Module):
def __init__(self):
super(FlowNet, self).__init__()
self.conv1 = nn.Conv2d(6, 64, kernel_size=7, stride=2, padding=3)
self.bn1 = nn.BatchNorm2d(64)
self.conv2 = nn.Conv2d(64, 128, kernel_size=5, stride=2, padding=2)
self.bn2 = nn.BatchNorm2d(128)
self.conv3 = nn.Conv2d(128, 256, kernel_size=5, stride=2, padding=2)
self.bn3 = nn.BatchNorm2d(256)
self.conv3_1 = nn.Conv2d(256, 256, kernel_size=3, stride=1, padding=1)
self.bn3_1 = nn.BatchNorm2d(256)
self.conv4 = nn.Conv2d(256, 512, kernel_size=3, stride=2, padding=1)
self.bn4 = nn.BatchNorm2d(512)
self.conv4_1 = nn.Conv2d(512, 512, kernel_size=3, stride=1, padding=1)
self.bn4_1 = nn.BatchNorm2d(512)
self.conv5 = nn.Conv2d(512, 512, kernel_size=3, stride=2, padding=1)
self.bn5 = nn.BatchNorm2d(512)
self.conv5_1 = nn.Conv2d(512, 512, kernel_size=3, stride=1, padding=1)
self.bn5_1 = nn.BatchNorm2d(512)
self.conv6 = nn.Conv2d(512, 1024, kernel_size=3, stride=2, padding=1)
self.bn6 = nn.BatchNorm2d(1024)
self.conv6_1 = nn.Conv2d(1024, 1024, kernel_size=3, stride=1, padding=1)
self.bn6_1 = nn.BatchNorm2d(1024)
self.conv7 = nn.Conv2d(1024, 1024, kernel_size=3, stride=2, padding=1)
self.bn7 = nn.BatchNorm2d(1024)
self.conv7_1 = nn.Conv2d(1024, 1024, kernel_size=3, stride=1, padding=1)
self.bn7_1 = nn.BatchNorm2d(1024)
self.fc1 = nn.Linear(1024 * 7 * 7, 4096)
self.fc2 = nn.Linear(4096, 4096)
self.fc3 = nn.Linear(4096, 2)
def forward(self, x):
x = self.conv1(x)
x = self.bn1(x)
x = nn.functional.relu(x)
x = self.conv2(x)
x = self.bn2(x)
x = nn.functional.relu(x)
x = self.conv3(x)
x = self.bn3(x)
x = nn.functional.relu(x)
x = self.conv3_1(x)
x = self.bn3_1(x)
x = nn.functional.relu(x)
x = self.conv4(x)
x = self.bn4(x)
x = nn.functional.relu(x)
x = self.conv4_1(x)
x = self.bn4_1(x)
x = nn.functional.relu(x)
x = self.conv5(x)
x = self.bn5(x)
x = nn.functional.relu(x)
x = self.conv5_1(x)
x = self.bn5_1(x)
x = nn.functional.relu(x)
x = self.conv6(x)
x = self.bn6(x)
x = nn.functional.relu(x)
x = self.conv6_1(x)
x = self.bn6_1(x)
x = nn.functional.relu(x)
x = self.conv7(x)
x = self.bn7(x)
x = nn.functional.relu(x)
x = self.conv7_1(x)
x = self.bn7_1(x)
x = nn.functional.relu(x)
x = x.view(-1, 1024 * 7 * 7)
x = self.fc1(x)
x = nn.functional.relu(x)
x = self.fc2(x)
x = nn.functional.relu(x)
x = self.fc3(x)
return x
# 加载Pytorch模型
pytorch_model = FlowNet()
pytorch_model.load_state_dict(torch.load('flownet.pth'))
# 转换为Keras模型
keras_model = Sequential()
keras_model.add(Conv2D(64, kernel_size=7, strides=2, padding='same', input_shape=(384, 512, 6)))
keras_model.add(BatchNormalization())
keras_model.add(Activation('relu'))
keras_model.add(Conv2D(128, kernel_size=5, strides=2, padding='same'))
keras_model.add(BatchNormalization())
keras_model.add(Activation('relu'))
keras_model.add(Conv2D(256, kernel_size=5, strides=2, padding='same'))
keras_model.add(BatchNormalization())
keras_model.add(Activation('relu'))
keras_model.add(Conv2D(256, kernel_size=3, strides=1, padding='same'))
keras_model.add(BatchNormalization())
keras_model.add(Activation('relu'))
keras_model.add(Conv2D(512, kernel_size=3, strides=2, padding='same'))
keras_model.add(BatchNormalization())
keras_model.add(Activation('relu'))
keras_model.add(Conv2D(512, kernel_size=3, strides=1, padding='same'))
keras_model.add(BatchNormalization())
keras_model.add(Activation('relu'))
keras_model.add(Conv2D(512, kernel_size=3, strides=2, padding='same'))
keras_model.add(BatchNormalization())
keras_model.add(Activation('relu'))
keras_model.add(Conv2D(512, kernel_size=3, strides=1, padding='same'))
keras_model.add(BatchNormalization())
keras_model.add(Activation('relu'))
keras_model.add(Conv2D(1024, kernel_size=3, strides=2, padding='same'))
keras_model.add(BatchNormalization())
keras_model.add(Activation('relu'))
keras_model.add(Conv2D(1024, kernel_size=3, strides=1, padding='same'))
keras_model.add(BatchNormalization())
keras_model.add(Activation('relu'))
keras_model.add(Conv2D(1024, kernel_size=3, strides=2, padding='same'))
keras_model.add(BatchNormalization())
keras_model.add(Activation('relu'))
keras_model.add(Conv2D(1024, kernel_size=3, strides=1, padding='same'))
keras_model.add(BatchNormalization())
keras_model.add(Activation('relu'))
keras_model.add(Flatten())
keras_model.add(Dense(4096))
keras_model.add(Activation('relu'))
keras_model.add(Dense(4096))
keras_model.add(Activation('relu'))
keras_model.add(Dense(2))
keras_model.add(Activation('softmax'))
# 复制参数
for i, layer in enumerate(keras_model.layers):
if 'conv' in layer.name:
layer.set_weights([pytorch_model.state_dict()['conv{}.weight'.format(i+1)].numpy(),
pytorch_model.state_dict()['conv{}.bias'.format(i+1)].numpy()])
elif 'bn' in layer.name:
layer.set_weights([pytorch_model.state_dict()['bn{}.weight'.format(i-1)].numpy(),
pytorch_model.state_dict()['bn{}.bias'.format(i-1)].numpy(),
pytorch_model.state_dict()['bn{}.running_mean'.format(i-1)].numpy(),
pytorch_model.state_dict()['bn{}.running_var'.format(i-1)].numpy()])
elif 'fc' in layer.name:
layer.set_weights([pytorch_model.state_dict()['fc{}.weight'.format(i-25)].numpy().T,
pytorch_model.state_dict()['fc{}.bias'.format(i-25)].numpy()])
在这个示例中,我们定义了一个FlowNet模型,并使用load_state_dict()函数加载Pytorch模型。然后,我们手动将Pytorch模型转换为Keras模型,并使用set_weights()函数复制参数。
方法2:使用pytorch2keras库
我们可以使用pytorch2keras库来自动将Pytorch模型转换为Keras模型。我们可以使用以下代码来使用pytorch2keras库。
import torch
from pytorch2keras.converter import pytorch_to_keras
from FlowNet import FlowNet
# 定义Pytorch模型
pytorch_model = FlowNet()
pytorch_model.load_state_dict(torch.load('flownet.pth'))
# 转换为Keras模型
keras_model = pytorch_to_keras(pytorch_model, input_var=(6, 384, 512))
在这个示例中,我们使用pytorch2keras库来自动将Pytorch模型转换为Keras模型。我们定义了一个FlowNet模型,并使用load_state_dict()函数加载Pytorch模型。然后,我们使用pytorch_to_keras()函数将Pytorch模型转换为Keras模型。
以FlowNet为例讲解
FlowNet是一个用于光流估计的深度学习模型。在这个示例中,我们将使用FlowNet模型来演示如何将Pytorch模型转换为Keras模型。
示例1:手动转换
我们可以使用上面的手动转换方法将Pytorch的FlowNet模型转换为Keras模型。
示例2:使用pytorch2keras库
我们可以使用pytorch2keras库将Pytorch的FlowNet模型自动转换为Keras模型。
import torch
from pytorch2keras.converter import pytorch_to_keras
from FlowNet import FlowNet
# 定义Pytorch模型
pytorch_model = FlowNet()
pytorch_model.load_state_dict(torch.load('flownet.pth'))
# 转换为Keras模型
keras_model = pytorch_to_keras(pytorch_model, input_var=(6, 384, 512))
在这个示例中,我们使用pytorch2keras库将Pytorch的FlowNet模型自动转换为Keras模型。我们定义了一个FlowNet模型,并使用load_state_dict()函数加载Pytorch模型。然后,我们使用pytorch_to_keras()函数将Pytorch模型转换为Keras模型。
总结
在将Pytorch模型转换为Keras模型时,我们可以手动转换或使用pytorch2keras库自动转换。手动转换需要我们了解Pytorch和Keras的模型结构和参数,而自动转换则可以自动完成这个过程。无论使用哪种方法,我们都可以将Pytorch模型转换为Keras模型,并在Keras中使用这个模型。
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