tf.cast转pytorch
时间: 2023-07-01 16:26:45 浏览: 93
在 PyTorch 中,可以使用 `tensor.type()` 或 `tensor.to(dtype)` 方法来实现 `tf.cast` 的功能,其中 `dtype` 参数可以指定目标数据类型。例如,将一个 FloatTensor 转换为 IntTensor,可以使用以下代码:
```python
import torch
float_tensor = torch.tensor([1.0, 2.0, 3.0])
int_tensor = float_tensor.to(torch.int)
```
此外,还可以使用 `tensor.float()`、`tensor.double()`、`tensor.long()` 等方法来转换数据类型。例如,将一个 IntTensor 转换为 FloatTensor,可以使用以下代码:
```python
import torch
int_tensor = torch.tensor([1, 2, 3])
float_tensor = int_tensor.float()
```
相关问题
讲一下tensorflow代码转为pytorch代码。def simulated_spectral9_camera_spectral_response_function(hyper_spectral_image,masked_response_function): masked_response_function = tf.cast(masked_response_function, dtype=hyper_spectral_image.dtype) ##9,31 hyper_spectral_image = hyper_spectral_image[:,1:-1, 1:-1,:] #裁切中心部分 batch_size,h,w,c = hyper_spectral_image.shape response3x3 = tf.reshape(masked_response_function,[3,3,31]) #padding到 h,w responsehxw = tf.tile(response3x3,[h//3,w//3,1]) response_img = hyper_spectral_image*responsehxw response_img = tf.reduce_sum(response_img,axis=-1)/ tf.reduce_sum(responsehxw,axis=-1) #,keepdims=True # 预期 shape: (batch, height, width, 1) return response_img
将 TensorFlow 代码转换为 PyTorch 代码,可以按照以下步骤进行:
1. 导入 PyTorch 库和相关模块:
```python
import torch
import torch.nn.functional as F
```
2. 将 `tf.cast` 方法替换为 `torch.Tensor.to()` 方法:
```python
# TensorFlow 代码
masked_response_function = tf.cast(masked_response_function, dtype=hyper_spectral_image.dtype)
# PyTorch 代码
masked_response_function = masked_response_function.to(hyper_spectral_image.dtype)
```
3. 将 `tf.reshape` 方法替换为 `torch.Tensor.view()` 方法:
```python
# TensorFlow 代码
response3x3 = tf.reshape(masked_response_function,[3,3,31])
# PyTorch 代码
response3x3 = masked_response_function.view(3, 3, 31)
```
4. 将 `tf.tile` 方法替换为 `torch.Tensor.repeat()` 方法:
```python
# TensorFlow 代码
responsehxw = tf.tile(response3x3,[h//3,w//3,1])
# PyTorch 代码
responsehxw = response3x3.repeat(h // 3, w // 3, 1)
```
5. 将 `tf.reduce_sum` 方法替换为 `torch.sum()` 方法:
```python
# TensorFlow 代码
response_img = tf.reduce_sum(response_img,axis=-1)/ tf.reduce_sum(responsehxw,axis=-1)
# PyTorch 代码
response_img = torch.sum(response_img, dim=-1) / torch.sum(responsehxw, dim=-1)
```
6. 将 TensorFlow 的 `None` 替换为 PyTorch 的 `None`:
```python
# TensorFlow 代码
keepdims=True
# PyTorch 代码
keepdim=True
```
7. 将 TensorFlow 的 `shape` 属性替换为 PyTorch 的 `size()` 或 `shape` 方法:
```python
# TensorFlow 代码
batch_size,h,w,c = hyper_spectral_image.shape
# PyTorch 代码
batch_size, h, w, c = hyper_spectral_image.size()
```
最终的 PyTorch 代码如下:
```python
import torch
import torch.nn.functional as F
def simulated_spectral9_camera_spectral_response_function(hyper_spectral_image, masked_response_function):
masked_response_function = masked_response_function.to(hyper_spectral_image.dtype)
hyper_spectral_image = hyper_spectral_image[:, 1:-1, 1:-1, :]
batch_size, h, w, c = hyper_spectral_image.size()
response3x3 = masked_response_function.view(3, 3, 31)
responsehxw = response3x3.repeat(h // 3, w // 3, 1)
response_img = hyper_spectral_image * responsehxw
response_img = torch.sum(response_img, dim=-1) / torch.sum(responsehxw, dim=-1, keepdim=True)
return response_img
```
有一个代码,代码是用tensorflow实现的 请问怎么修改可以改成用pytorch实现啊
首先,需要了解tensorflow和pytorch的差异和相似之处,以便能够更好地将代码从tensorflow转换到pytorch。
一些常见的tensorflow和pytorch的差异包括:
1. 数据类型:tensorflow默认使用32位浮点数,而pytorch默认使用64位浮点数。因此,需要在转换代码时注意数据类型的匹配。
2. 前向传播和反向传播:tensorflow和pytorch的前向传播和反向传播有些不同,需要根据pytorch的计算图和反向传播机制来修改代码。
3. 模型结构:tensorflow和pytorch的模型结构有些不同,需要根据pytorch的模型结构来修改代码。
下面是一些可能需要修改的代码示例:
1. 导入库
tensorflow:
```
import tensorflow as tf
```
pytorch:
```
import torch
```
2. 定义模型
tensorflow:
```
x = tf.placeholder(tf.float32, [None, 784])
W = tf.Variable(tf.zeros([784, 10]))
b = tf.Variable(tf.zeros([10]))
y = tf.matmul(x, W) + b
```
pytorch:
```
class Model(torch.nn.Module):
def __init__(self):
super(Model, self).__init__()
self.linear = torch.nn.Linear(784, 10)
def forward(self, x):
out = self.linear(x)
return out
model = Model()
```
3. 前向传播和反向传播
tensorflow:
```
cross_entropy = tf.reduce_mean(
tf.nn.softmax_cross_entropy_with_logits(labels=y_, logits=y))
train_step = tf.train.GradientDescentOptimizer(0.5).minimize(cross_entropy)
```
pytorch:
```
criterion = torch.nn.CrossEntropyLoss()
optimizer = torch.optim.SGD(model.parameters(), lr=0.5)
for epoch in range(num_epochs):
for i, (images, labels) in enumerate(train_loader):
images = images.view(-1, 784)
outputs = model(images)
loss = criterion(outputs, labels)
optimizer.zero_grad()
loss.backward()
optimizer.step()
```
4. 训练模型
tensorflow:
```
with tf.Session() as sess:
sess.run(tf.global_variables_initializer())
for i in range(1000):
batch_xs, batch_ys = mnist.train.next_batch(100)
sess.run(train_step, feed_dict={x: batch_xs, y_: batch_ys})
correct_prediction = tf.equal(tf.argmax(y, 1), tf.argmax(y_, 1))
accuracy = tf.reduce_mean(tf.cast(correct_prediction, tf.float32))
print(sess.run(accuracy, feed_dict={x: mnist.test.images, y_: mnist.test.labels}))
```
pytorch:
```
for epoch in range(num_epochs):
for i, (images, labels) in enumerate(train_loader):
images = images.view(-1, 784)
outputs = model(images)
loss = criterion(outputs, labels)
optimizer.zero_grad()
loss.backward()
optimizer.step()
correct = 0
total = 0
for images, labels in test_loader:
images = images.view(-1, 784)
outputs = model(images)
_, predicted = torch.max(outputs.data, 1)
total += labels.size(0)
correct += (predicted == labels).sum()
accuracy = 100 * correct / total
print('Epoch [{}/{}], Loss: {:.4f}, Accuracy: {:.2f}%'
.format(epoch + 1, num_epochs, loss.item(), accuracy))
```
需要注意的是,这只是一些可能需要修改的代码示例。在实际转换代码时,需要更加具体地根据实际情况进行修改。