[PyTorch 1.1 : Getting Started : サンプルによる PyTorch の学習 –
PyTorch](http://torch.classcat.com/2019/06/25/pytorch-1-1-getting-started-
pytorch-with-examples/)

上記サイトのコードを参考に、質問に載せたコードを実行するとエラーが出てきて困っております。

**実行環境**  
python3.7.6  
pytorch1.3.1  
numpy1.17.4

gpu:GeForce GTX 1660 Ti  
Cuda:10.1  
Cudnn:7.6.5

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**実行したコード**

```

    # -*- coding: utf-8 -*-
    
    import torch
    
    dtype = torch.float
    device = torch.device("cpu")
    dtype = torch.device("cuda:0") # Uncomment this to run on GPU
    print("dtype:", dtype)
    
    # N is batch size; D_in is input dimension;
    # H is hidden dimension; D_out is output dimension.
    N, D_in, H, D_out = 64, 1000, 100, 10
    
    # Create random input and output data
    x = torch.randn(N, D_in, device=device, dtype=dtype)
    y = torch.randn(N, D_out, device=device, dtype=dtype)
    
    # Randomly initialize weights
    w1 = torch.randn(D_in, H, device=device, dtype=dtype)
    w2 = torch.randn(H, D_out, device=device, dtype=dtype)
    
    learning_rate = 1e-6
    for t in range(500):
        # Forward pass: compute predicted y
        h = x.mm(w1)
        h_relu = h.clamp(min=0)
        y_pred = h_relu.mm(w2)
    
        # Compute and print loss
        loss = (y_pred - y).pow(2).sum().item()
        print(t, loss)
    
        # Backprop to compute gradients of w1 and w2 with respect to loss
        grad_y_pred = 2.0 * (y_pred - y)
        grad_w2 = h_relu.t().mm(grad_y_pred)
        grad_h_relu = grad_y_pred.mm(w2.t())
        grad_h = grad_h_relu.clone()
        grad_h[h < 0] = 0
        grad_w1 = x.t().mm(grad_h)
    
        # Update weights using gradient descent
        w1 -= learning_rate * grad_w1
        w2 -= learning_rate * grad_w2
    
```

**エラーメッセージ**

```

    dtype: cuda:0
    Traceback (most recent call last):
      File "c:\program files (x86)\microsoft visual studio\2019\community\common7\ide\extensions\microsoft\python\core\ptvsd_launcher.py", line 119, in <module>
        vspd.debug(filename, port_num, debug_id, debug_options, run_as)
      File "c:\program files (x86)\microsoft visual studio\2019\community\common7\ide\extensions\microsoft\python\core\Packages\ptvsd\debugger.py", line 39, in debug
        run()
      File "c:\program files (x86)\microsoft visual studio\2019\community\common7\ide\extensions\microsoft\python\core\Packages\ptvsd\__main__.py", line 316, in run_file
        runpy.run_path(target, run_name='__main__')
      File "C:\Users\U\.conda\envs\env\lib\runpy.py", line 263, in run_path
        pkg_name=pkg_name, script_name=fname)
      File "C:\Users\U\.conda\envs\env\lib\runpy.py", line 96, in _run_module_code
        mod_name, mod_spec, pkg_name, script_name)
      File "C:\Users\U\.conda\envs\env\lib\runpy.py", line 85, in _run_code
        exec(code, run_globals)
      File "D:\exam\tensor.py", line 16, in <module>
        x = torch.randn(N, D_in, device=device, dtype=dtype)
    TypeError: randn() received an invalid combination of arguments - got (int, int, dtype=torch.device, device=torch.device), but expected one of:
     * (tuple of ints size, tuple of names names, torch.dtype dtype, torch.layout layout, torch.device device, bool pin_memory, bool requires_grad)
     * (tuple of ints size, torch.Generator generator, tuple of names names, torch.dtype dtype, torch.layout layout, torch.device device, bool pin_memory, bool requires_grad)
     * (tuple of ints size, torch.Generator generator, Tensor out, torch.dtype dtype, torch.layout layout, torch.device device, bool pin_memory, bool requires_grad)
     * (tuple of ints size, Tensor out, torch.dtype dtype, torch.layout layout, torch.device device, bool pin_memory, bool requires_grad)
    
```
CC BY-SA 4.0
2020-01-08T11:57:50.237
62071
2020-02-05T00:51:28.390
2020-01-08T12:06:47.837
3060
37372
question
python pytorch
PyTorch Tensor 使用時のエラー
`dtype = torch.device("cuda:0")` としてしまっているのが原因でしょう。  
記事では `device = torch.device("cuda:0")` となっていますね。

* * *

_この投稿は[@metropolis
さんのコメント](https://ja.stackoverflow.com/questions/62071/pytorch-
tensor-%e4%bd%bf%e7%94%a8%e6%99%82%e3%81%ae%e3%82%a8%e3%83%a9%e3%83%bc#comment67722_62071)
の内容を元に コミュニティwiki として投稿しました。_
CC BY-SA 4.0
2020-02-05T00:51:28.390
62781
2020-02-05T00:51:28.390
3060
62071
answer